English literature states that auxiliary consists of (1) be, namely is, am, are, was, were, being, and been (2) have, namely, have, has, having, and had, and (3) do, namely, do, does, and did (4) modal, namely, will, shall, must, should, would, may, might, can, and could. So it can be understood that modal is part of auxiliary verb. So what is the difference? Auxiliary verbs other than modal do not have a literal meaning, for example is, am, are we do not know what they mean, while modal consisting of will, must, can, et al. they have a literal meaning, for example will akan, must harus, and can dapat. It's just that their function is the same, namely as a helping verb. For more details, please read the discussion between auxiliary and modal at THIS link .
| AUXILIARY | USES | PRESENT/FUTURE | PAST |
|----------------|----------------------------------------|-----------------------------------------------------------------|------------------------------------------------------------------|
| May | Polite request | May I borrow your pen? | |
| | Formal Permission | You may leave the room | |
| | Less than 75% certainty | -- Where is John? He may be at the library | He may have been at the library |
| Might | Less than 50% certainty | --Where is John? He might be at the library | He might have been at the library |
| | Polite request (rare) | Might I borrow your pen? | |
| Should | Advisability | I should study tonight | I should have studied last night |
| | 90% certainty | She should do well on the test. (future only, not present) | She should have done well on the test |
| Ought to | Advisability | I ought to study tonight | I ought to have studied last night |
| | 90% certainty | She ought to do well on the test. (future only, not present) | She ought to have done well on the test |
| Had better | Advisability with threat of bad result | You had better be on time, or we will leave without you. | (past form uncommon) |
| Be supposed to | Expectation | Class is supposed to begin at 10 this morning | Class was supposed to began at 10 yesterday morning |
| Be to | Strong expectation | You are to be here at 09:00 | You were to be here at 09:00 |
| Must | Strong necessity | I must go to class today | I had to go to class yesterday |
| | Prohibition (negative) | You must not open that door | |
| | 95% certainty | John isn’t around. He must be sick. (present only) | John must have been sick yesterday |
| Have to | Necessity | I have to go to class today | I had to go to class yesterday |
| | Lack of necessity (negative) | I do not have to go to office today | I did not have to go to office yesterday |
| Have got to | Necessity | I have got to go to class today | I had to go to class yesterday |
| Will | 100% certainty | He will be here at 06:00 (future only) | |
| | Willingness | --The phone is ringing I will get it | |
| | Polite request | Will you pass the book please | |
| Be going to | 100% certainty | He is going to be here at 06:00 (future only) | |
| | Definite plan | I am going to paint my room (future only) | I was going to paint my room, but I did not have time. |
| Can | Ability/Possibility | I can run fast | I could run fast when I was a child, but now I can’t |
| | Informal permission | You can use my car tomorrow | |
| | Informal polite request | Can I borrow your pen? | |
| | Impossibility (negative only) | That cannot be true!! | That cannot have been true!! |
| Could | Past ability | | I could run fast when I was a child |
| | Polite request | Could I borrow your pen? Could you help me? | |
| | Suggestion | --I need help in math You could talk to your teacher | You could have talked to your teacher |
| | Less than 50% certainty | --Where is John? He could be at home | He could have been at home |
| | Impossibility (negative only) | That could not be true!! | That could not have been true!! |
| Be able to | Ability | I am able to help you. I will be able to help you. | I was able to help him |
| Would | Polite request | Would you please pass the salt? Would you mind if I left early? | |
| | Preference | I would rather go to the park than stay home. | I would rather have gone to the park. |
| | Repeated action in the past | | When I was a child, I would visit my grandparents every weekend. |
| Used to | Repeated action in the past. | | I used to visit my grandparents every weekend. |
| Shall | Polite question to make a suggestion | Shall I open the window? | |
| | Future with ‘I’ or ‘we’ as subject | I shall arrive at 09:00 (will = more common) | |Learn Auxiliary Verbs
Auxiliary verbs are additional verbs used together with the main verb to add meaning. Be, have, do, and modal are auxiliary verbs. The TOEFL exam often contains questions about auxiliary verbs.
Example in a sentence:
1. BE + -ing
The farmers are cultivating a new plant variety to gain their harvest.
2. HAVE + participle
The farmers have cultivated a new plant variety to gain their harvest.
3. MODAL + verb word.
The farmers should cultivate a new plant variety to gain their harvest
Example questions in the TOEFL test:
The game is interesting, but all the participants are struggling.
A B C D
Question analysis
The answer you should choose is D. Participants struggling should be participants are struggling. Subject + BE + Verb -ing.
Correct answer
The game is interesting, but all the participants are struggling
In Indonesian: The game is interesting, but all participants are struggling.
In auxiliary verbs, what you should pay attention to is:
- always use BE for -ing verbs
- always use HAVE for participles, and
- always use modals for verbs
So in the question above the use of the verb -ing (struggling) without preceded by BE is not permitted.
Formula for passive auxiliary verbs
S + BE + participle
- A new plant variety is cultivated by the farmers to gain their harvest.
- A new plant variety has been cultivated by the farmers to gain their harvest.
- A new plant variety should be cultivated by the farmers to gain their harvest.