Tenses, Modals and Subject-Verb Concord

Most students meet tenses as a grid of twelve boxes and then spend two years forgetting which box is which. There is an easier way in. An English verb form carries two pieces of information, not one. The first is time — present, past or future. The second is aspect, which is the angle from which the speaker looks at the action. English has four such angles: simple, continuous, perfect and perfect continuous. Three times multiplied by four aspects gives the twelve forms, and every single one of them is built from the same small set of helping verbs.

Before the forms make sense you need the parts of a verb. Take write. The base form is write, the third person singular form is writes, the -ing form is writing, the past form is wrote and the past participle is written. Regular verbs make the last two by adding -ed, as in walk, walked, walked; irregular verbs change shape, as in go, went, gone. Everything that follows is these parts plugged into three helpers: be, have and will.

Here is the whole system in one line each. The continuous aspect is be + -ing form, and it pictures the action as running rather than finished. The perfect aspect is have + past participle, and it says the action is complete but is being viewed from a later point. The perfect continuous is have + been + -ing form, and it measures how long something has been going on up to that later point. The simple aspect adds no aspect helper at all; in the present and the past a plain statement needs no helping verb, and in the future it takes only will with the base form.

Watch one verb travel through the three times in each aspect. Read these across, not down:

• Simple: Our bus leaves at seven. / Our bus left at seven. / Our bus will leave at seven.
• Continuous: The bus is leaving now. / The bus was leaving when I reached the gate. / At this time tomorrow the bus will be leaving.
• Perfect: The bus has already left. / The bus had already left when I reached the gate. / The bus will have left by the time you get there.
• Perfect continuous: We have been waiting since seven o’clock. / We had been waiting for twenty minutes when the bus came. / By June we will have been waiting for a year.

Two form rules do most of the policing. First, only the first word of a verb phrase changes for person and number; the rest stay exactly as they are. Compare She has been writing with They have been writing — the part been writing never moves. Second, once you have chosen a helping verb, the shape of the next verb is decided for you: inside these tense forms, be is followed by the -ing form, have by the past participle, and will by the base form. That is why She has wrote can never be right; have demands written, and nothing else will do.

Ask what the speaker wants to stress and the present forms sort themselves out quickly.

The simple present is for what is generally true. It covers habits and routines (My sister practises the tabla every evening.), timetables and fixed programmes (The library closes at five.), and facts that do not change with time (Water boils at 100 degrees Celsius.). Words such as always, usually, often, rarely, never, every day and on Sundays point straight at it. Keep the ending in mind: the -s belongs to the third person singular alone, so it is He walks to school but They walk to school.

The present continuous pictures an action in progress around the moment of speaking (Listen! Someone is knocking at the door.) or a situation that is only temporary (She is staying with her cousin this month.). It also does duty as a future form when the plan is already fixed: I am meeting my class teacher on Friday. One trap sits here, and it is easy to slide past while editing. Verbs that describe a state rather than an activity — know, believe, understand, own, belong, contain, seem, prefer — are normally not used in the continuous at all. Write I know the answer, never I am knowing the answer.

The present perfect ties a finished action to the present moment. Use it when the result still matters (She has lost her keys, and so she cannot get in), when the time is deliberately left unstated (I have read that novel twice), and when the period being spoken about is still running (We have had three tests this week). It sits comfortably with just, already, yet, ever, never, so far, recently and this week. Its one hard rule is worth writing on the inside of your notebook: a finished past time cannot appear with it. I saw him yesterday is right; I have seen him yesterday is not English.

The present perfect continuous answers the question how long? for something that is still going on: It has been raining since morning. Here since takes a point in time (since Monday, since 2019, since four o’clock) while for takes a stretch of time (for two hours, for a week, for ages). The two are easy to mix up, and just as easy to put right once you know which is which. The difference between the last two forms is really the difference between a finished job and an unfinished one. I have painted the gate means the gate is now painted and the work is over; I have been painting the gate means I am still at it, and there is probably paint on my hands.

For the past forms, one question does nearly all the work: which action came first, and which one was still running?

The simple past names a completed action, usually with its time attached: The match ended at six o’clock. The past continuous supplies the longer action that was already running when something cut across it, and the two normally appear together, joined by when or while: While I was doing my homework, the lights went out. The long background action takes was or were plus the -ing form; the short interrupting action takes the simple past. Two long actions running side by side both take the continuous: My mother was cooking while I was laying the table.

The past perfect exists for one job only, and knowing that job is enough. It marks the earlier of two past actions: The train had left before we reached the station. Notice that the order of events, not the order of the words, decides which verb gets the past perfect. Expressions such as by the time, no sooner ... than and hardly ... when usually drag it into the sentence: By the time the guests arrived, my mother had cooked everything. The past perfect continuous adds length to that earlier stretch: She had been studying for three hours before her friends called.

For a habit that belonged to the past and has since stopped, used to is the natural choice: We used to walk to school in Class 6. Watch the form, because it is easy to get wrong. It is used to plus the base verb, and in the negative it becomes did not use to, with the -d gone.

The future is not a single tense but a set of choices, and each choice carries its own shade of meaning. will plus the base form makes a prediction, a promise or a decision taken on the spot: I will help you with that. be going to reports a plan already made, or a prediction based on evidence in front of you: Look at those clouds — it is going to rain. The present continuous covers a fixed arrangement with people and times already settled (We are visiting my grandparents on Sunday.), and the simple present covers a published timetable (The train leaves at 6:40.). Shall survives chiefly in offers and suggestions: Shall I carry that for you?

Two more forms complete the set. will have plus the past participle looks back from a point in the future (By Friday we will have finished the syllabus.), and will have been plus the -ing form measures duration up to that point. Finally, one rule is worth fixing firmly in mind. After when, before, after, until, as soon as and by the time, English uses a present form for future meaning and never will. Write We will start as soon as the rain stops, not as soon as the rain will stop. The same logic runs the first conditional: If it rains tomorrow, the match will be postponed.

A modal never names an action by itself. It adds an attitude to the action that some other verb names — how likely it is, how necessary it is, whether it is allowed. The form rules are short and absolute. A modal is followed by the base form of the verb; it never takes -s in the third person; it never takes to after it, with ought to as the one exception; and two modals cannot stand side by side. So She can swim and He must go are right, while She cans swim, He must to go and He will can come are all impossible.

Permission. May is the formal choice, the one for a teacher or a stranger: May I come in, sir? Can is the everyday equivalent (You can borrow my notes.), while could and might sound more tentative and therefore more polite. Permission is refused with may not, and an action is forbidden outright with must not: Visitors must not enter the laboratory.

Obligation. Must carries strong necessity that the speaker feels personally or that a law imposes: You must wear a helmet. Have to reports an obligation that comes from outside the speaker — a school rule, a timetable, somebody else’s decision: We have to submit the project by Monday. The negatives are where care is needed, because they do not mean opposite versions of the same thing. You must not go forbids you from going. You need not go and You do not have to go say only that going is unnecessary; you are still free to go if you wish.

Ability. Can covers ability in the present (He can solve quadratic equations easily.) and could covers ability spread over past time (At six she could already read the newspaper.). Modals have no infinitive and no participle, so be able to steps in wherever a modal cannot go: I have not been able to reach him all day.

Possibility and deduction. May, might and could report something as possible, with might sounding the least certain of the three: She may be in the staff room. Must and cannot do a quite different job here. They express a confident conclusion drawn from evidence, and this use is easy to misread as an order. He must be tired; he has been working since morning is not an order at all but a deduction, and That cannot be her brother; she has no brother is the confident denial that matches it.

Advice and requests. Should and ought to give advice or state a duty: You should revise that diagram once more. Had better is stronger and hints at trouble if the advice is ignored, and it too is followed by the base form with no to: You had better see a doctor about that cough. For requests, could and would are gentler than can and will: Could you please repeat the last line? Any of these attitudes can be shifted into the past by adding have and the past participle: You should have told me earlier, She must have missed the bus, They might have forgotten the address.

Concord simply means agreement. A singular subject takes a singular verb and a plural subject takes a plural verb; that is the whole rule. Every difficulty that follows comes from identifying which word is actually the subject, because English cheerfully drops long phrases between the subject and its verb and lets you trip over them.

Begin with the most confusing feature of the language. On a noun, the ending -s usually marks the plural; on a verb in the simple present, the ending -s marks the singular. The boy runs carries the -s on the verb, while The boys run carries it on the noun. In a correct present-tense sentence the two -s endings never appear together, and that single observation is worth applying to every subject and verb you check.

Next, train yourself to cross out whatever sits between the subject and the verb. In The box of old letters was lying under the bed, the subject is box and not letters, so the verb is singular. In The list of selected candidates has been put up on the notice board, the subject is list. A good habit while editing is to run a line through every phrase beginning with of, with, in, from or among and then look at what is left standing.

Certain link words look as though they are adding a second subject, but they are doing nothing of the kind. Along with, together with, as well as, in addition to, besides, accompanied by and including leave the number of the subject exactly as it was: The teacher, along with her students, was invited to the function. The subject is still teacher, and the commas are a hint that the phrase is an extra. Compare The teacher and her students were invited to the function, where and genuinely builds a plural subject.

Then there are sentences in which the subject arrives after the verb. In There is a book on the desk and There are two books on the desk, the word there is only a placeholder and the verb agrees with the noun that follows it. The same happens in questions (Where are your shoes?) and in sentences that open with a phrase of place (On the wall hang two old photographs.). In each case, find the real subject first and only then choose the verb.

Three quick pairs close the section. One of my friends lives abroad takes a singular verb, because the subject is one even though friends stands right next to the verb. The number of applicants has increased is singular while A number of applicants have applied late is plural, because the number names one figure whereas a number of just means many. And an amount treated as a single block takes a singular verb: Five years is a long time to wait, Ten kilometres is too far to walk on a hot afternoon.

Some subjects refuse to behave the way their spelling suggests, and those are the ones that repay a little deliberate memorising. Learn them as a short, definite list rather than trusting your ear.

Collective nouns. Words such as team, family, class, jury, committee, crowd, audience, government and staff name a group of people as one body. When the group acts together, the verb is singular: The team is playing well today. When the sentence shows the members behaving separately or disagreeing with one another, a plural verb becomes possible: The jury were divided in their opinions. The clue is always in the rest of the sentence, since words like their, among themselves and one another pull the members apart. If nothing in the sentence separates them, choose the singular.

Each, every, either and neither. All four are singular when they are the subject, however plural the noun beside them may look. Each of the boys was given a certificate. Every student has to bring an identity card. Neither of the answers is correct. Two related points are worth adding. When every joins two singular nouns, the verb stays singular: Every boy and every girl was present. But when each comes after a plural subject, the subject rules and the verb is plural: They each have a copy of the map.

Either ... or, neither ... nor, not only ... but also. With these paired connectors the verb agrees with the subject nearest to it. Neither the teacher nor the students were satisfied takes a plural verb because students stands closest. Turn the pair around and the verb changes with it: Neither the students nor the teacher was satisfied. By contrast, two subjects joined by and normally take a plural verb, unless the two words name a single thing or a single person: Bread and butter is her usual breakfast, and The Principal and Manager has signed the notice when one person holds both posts.

Nouns that look plural but are not. News, mathematics, physics, economics, civics, measles and mumps all end in -s and all take a singular verb: The news from the flooded districts is worrying. Mathematics is her favourite subject.

Nouns that are plural without an -s, and nouns that have no singular. People, police, cattle and poultry take plural verbs: The police have arrested two suspects. Cattle are grazing in the field. Tools and garments made of two matching parts — scissors, spectacles, trousers, jeans, pliers, tongs — are plural, so These scissors are blunt, although A pair of scissors is lying on the table becomes singular because the head word is now pair. Last of all, uncountable nouns such as furniture, luggage, information, advice, equipment, machinery, scenery and stationery never take an -s and always take a singular verb: The furniture in the new office is expensive. Writing furnitures or informations is an error of the noun as well as of the verb.

Grammar reaches you as applied work rather than as definitions to reproduce, so a fixed working order matters as much as the rules themselves. Two formats are the ones to be ready for: filling blanks in a short passage, and repairing a passage in which something has gone wrong in each line.

Gap filling. Read the whole passage once before you write a single word. A paragraph normally sits inside one time frame, and the sentences around a blank quietly tell you what that frame is. Then work through four checks in a fixed order. First, find the subject of the blank and decide whether it is singular or plural. Second, fix the time from the passage or from a signal word such as yesterday, since 2018, next week, already or every morning. Third, choose the aspect: is the action being named as a whole, pictured as running, looked back at from a later point, or measured for how long it has lasted? Fourth, write the form out completely, helping verb and all, and check the ending of the main verb against the helper you have chosen.

Try the method on three blanks. In Rohit ______ (wait) at the bus stop since seven o’clock, the subject is singular, since fixes a starting point, and the waiting is still going on, so duration is what is being measured: the answer is has been waiting. In By the time we reached the hall, the programme ______ (begin), both actions are past and one is plainly earlier, so the answer is had begun. In If the weather clears, we ______ (go) for a walk, the if clause is already in the present, so the main clause takes will go.

Editing and omission. In an editing task there is one mistake in each line and you copy out the incorrect word beside its correction. In an omission task a word has been left out, and you show the word before the gap, the missing word and the word after. Either way you change exactly what is asked and not one thing more. Do not improve the style, do not rewrite the sentence, and copy the spelling of every word you carry across, because a word copied with a spelling slip is no longer the correction that was asked for.

Run the same order of checks along each line: concord first, then tense consistency, then articles (a, an, the), then prepositions, then determiners and quantifiers (much, many, little, few), then word form (careless against carelessly), then pronouns, then connectors. Here are five lines of the kind you will meet, each with the single change it needs:

• Every year our school organise a science fair. Change organise to organises, because school is a singular subject.
• The exhibits was arranged in the main hall. Change was to were, because exhibits is plural.
• Each of the classes prepare three models. Change prepare to prepares, because the subject is each and not classes.
• Neither the teachers nor the principal were present. Change were to was, because the nearer subject is the singular principal.
• The news of the results have spread quickly. Change have to has, because news takes a singular verb.

Two habits are worth building deliberately. Say the subject and the verb aloud with everything in between removed — school ... organises, news ... has, box ... was — because the ear catches what the eye slides straight past. And when you have finished, read your completed passage once as a whole. A wrong tense almost always announces itself by clashing with the sentence sitting next to it.