Auxiliaries can be organized into two groups. The first of these groups consists of the three high-frequency auxiliaries be, have, and do. Besides functioning as auxiliaries, they may also be used as verbs.
- Carlos is a marketing manager.
- Yvette has six children.
- The Wyatt brothers do business efficiently.
When be is used as an auxiliary verb, it is combined with a present participle.
- Carlos is setting goals for the year to come.
When have is used as an auxiliary verb, it is combined with a past participle.
- Yvette has done all she can to raise them.
And when do is used as an auxiliary, it can be used with not to negate a statement; it can also introduce a question or add emphasis to a statement.
- The Wyatt brothers don’t like to lose their investors.
- Do you spend a lot of time at the library?
- We do go to the library on Saturdays, if not during the week.
A second group of auxiliaries is the modal auxiliaries. Some of the most frequently used modal auxiliaries are be to, be supposed to, may, might, must, can, could, had better, have to, have got to, ought to, should, used to, and would. For the most part, these auxiliaries express the speaker’s mind-set or mood. In addition, modal auxiliaries may indicate possibility, permission, obligation, or ability.
- They should talk to their parents about it.
- Every morning I would drive 15 miles to work.
- I might be able to finish the kitchen by tonight.
Modal auxiliaries always precede the verb in the sentence, regardless of the verb form, including the addition of the auxiliaries be, have, and do. Modal auxiliaries (except those that include be or have) do not change form for number, and some make no tense changes.
When used in the present tense, most modal auxiliaries are followed by the base form of the verb.
- Mom might make fried chicken tonight.
- They must consider every possibility.
In order to form a question with a modal auxiliary, move the auxiliary to the beginning of the sentence in front of the subject.
- Can you lift this heavy box?
- May our friends join you for lunch?
To form a negative statement with a modal auxiliary, place the word not immediately after the modal auxiliary and before all other auxiliary verbs.
- I cannot understand a word she says.
- Maybe she should not have borrowed that winter jacket.
Would and could specify a desired or hypothetical situation. These two auxiliaries are often used in a main clause when if + a subjunctive form is used in the other clause.
- He would really like to eat one.
- I wish I could go horse riding.
- If I were a rich man, I would build homeless shelters everywhere.
Would is also used to indicate a habitual action.
- I would often go to the movies with my sister.
Can indicates the ability to do something. Note that its past form is could.
- Walking down that road can be dangerous.
- Man can travel far into outer space.
- She could not see where the road ended.
Whereas can indicates the ability to do something, may indicates that something is acceptable. In casual speech, however, can is often substituted for may.
- Anne may borrow my car if she needs to.
- Anne can borrow my car if she needs to.
The first sentence above indicates that Anne has permission to borrow the car, while the second sentence indicates that Anne has the ability to borrow it, or, if used casually, that she has permission to borrow it.
Although there is no clear-cut rule, may is usually used to make polite requests.
- May I have one of those forms, please?
- Dad, may we go swimming today?
Must indicates necessity or requirement; it can also express certainty.
- We must obtain a license before we can sell liquor.
- I must insist that you finish the job by dusk.
- If he’s not here, he must have been delayed.
May and might can both indicate uncertainty or possibility.
- I may have to go to New York this weekend.
- The children may need a flu shot.
- We might have another storm tonight.
- You might be right.
Had better and ought to suggest that something needs to be done and imply advisability.
- You had better be on time for your own party.
- She really ought to find new friends.
Shades of meaning
Ought to and had better express advisability. But besides expressing advisability, ought to, as well as should, may suggest that care be taken in carrying out the action of the verb. In addition, they may imply duty or responsibility in carrying out that action.
|ADVISABILITY||You ought to stay here till the storm ends.|
You had better stay here till the storm ends.
|SUGGESTION||You should try harder.|
You ought to try harder.
|DUTY OR RESPONSIBILITY||Children should follow the school’s safety regulations.|
Children ought to follow the school’s safety regulations.
Had better is similar in meaning to ought to and should, but it is usually stronger. The auxiliary had better often expresses a warning. It is followed by the basic form of the verb and has either a present or future meaning.
- Our left front tire is almost flat. We had better stop to fill it with air.
- She had better clean that wound as soon as possible, or it might get infected.
Like the auxiliary verb had, the verb had in the auxiliary had better can contract with a subject pronoun: you’d better, they’d better, and so on.
The past form of should is composed of should have + past participle.
- I had an exam this morning. I didn’t do well on it, because I read the wrong chapter. I should have been more attentive in class.
- It feels like I really hurt my ankle. I should not have played soccer for so long this afternoon.
The past form of ought to is composed of ought to have + past participle.
- I ought to have read the right chapter.
- You ought to have thought about the consequences before you volunteered.
Have to and have got to express necessity. Like must, they suggest that there is no other choice.
- All candidates have to take the grammar test.
- I simply have got to get there on time.
In informal conversation, must usually carries a stronger connotation than have to and often indicates a sense of urgency.
- I have to speak to Robert. I was hoping we could get together for lunch.
- I must speak to Robert immediately. His brother was in a car accident.
The past tense of have to is had to.
- I have to leave by tomorrow morning.
- I had to leave by this morning.
Have to and must, when in the negative, express lack of necessity or prohibition. Do not have to indicates that something is unnecessary, while must not indicates that something is not allowed.
- Tomorrow is Christmas, and we do not have to go to work.
- You must not tamper with that device.
Be supposed to and be to express expectation. They suggest that someone is expecting something about a scheduled situation, the fulfillment of conditions, or the use of proper procedures.
If used in conversation, be to is usually stronger in meaning and more clear-cut than be supposed to.
- The plane is supposed to take off in an hour.
- The plane is to take off at ten in the morning.
In the first example, the speaker expects the flight to take off in an hour, because that’s when it is scheduled to depart. The second sentence is similar in meaning to the first sentence, but it states a fact. The speaker knows with certainty when the plane will be taking off.
Be to and be supposed to can also express expectation about behavior.
- I am supposed to go to this meeting. My director told me he would be pleased to see me there.
- I am to be at this meeting. My director told us it is mandatory.
Used to expresses a habitual action in the past, one that is no longer performed or repeated. Used to can be used interchangeably with would in this sense. However, since would also has other meanings, it requires an indication of past time to make sense. Compare the following sets of examples.
- I used to go surfing every summer.
- When I was a teenager, I would go surfing every summer.
- I used to run five miles every morning.
- Before I broke my knee, I would run five miles every morning.
In modern English, shall has generally been replaced by will. In the past, shall was used as the first-person form of will to express the future tense. Nowadays, shall is usually used in a context where the speaker wishes to sound very polite or very formal.
When shall and will are used in questions, however, their meanings differ greatly. Will indicates the future tense, while shall (when used before I or we) means that the speaker is making a suggestion or asking someone else whether he or she agrees with the suggestion being made.
- Will we drive to the nearest gas station?
- Will we get a cup of tea?
- Shall we drive to the nearest gas station?
- Let’s go, shall we?
Let’s (let us) and why don’t are modal auxiliaries that are used to make suggestions or friendly or polite commands.
- Let’s go to a movie.
- Why don’t you pick me up at eight or so?