Auxiliaries and Modals
The 'be' verbs [ am, is, was, are, were], have and do are used to make tense forms, questions , passive forms and negatives. So they are called auxiliary / helping verbs. Can, Could, may, ,might, will, would, shall, should, must, dare, need, ought to, used to are called modal verbs.
(I) To from continuous tense:
- They are praying for good monsoon.
- He is playing hockey.
(II) To from passive form:
- The gate was closed.
- They were led by the guide.
(III) With infinitives :
(a) to indicate a plan, arrangement etc.
- I am to meet the doctor tomorrow.
- She is to be here by 4 p.m..
(b) to indicate command :
- She is to attend the interview.
- You are to surrender yourself at once.
It is used:
(I) in the formation of perfect tense :
- He has finished his work.
- They have decorated the hall.
(II) 'have to' with infinitives to show obligation.
- You have to obey the rules.
- She has to submit the papers today.
(III) 'Had to' - to show obligation in the past.
- They had to adopt a child.
- We had to file a case against him.
It is used:
(I) in the formation of negative and interrogative:
- Catherine does not practice regularly.
- She did not win the case.
- We do not expect anything from you.
- Does the like to join the course?
- Did you renew your card?
- Do they take rest now?
(II) To avoid repetition of a verb:
- Did she finish her work? - Yes, she did. [You need not say - " Yes , she finished her work"]
(III) to emphasize something:
- We do need a loan now. [ Getting a loan is a must]
- A strict warming was given. But the children did enter the garden.
(IV) To persuade something with request or invitation.
- Do stand in a line, please.
- Do come and bless our child.
D. Can, Could, may, might.
(I) Can express ability or capability
- I can climb up the hill.
- They can win the dance competition.
- Can you carry this bag to the station?
(II) May is used to show possibility in affirmative sentence:
- She may come next week.
- They may attend the party.
(III) Can and may - express permission : [ 'may' is formal]:
- She can / may use my dictionary.
- can / may I use your camera?
(IV) can is used in corresponding interrogative and negative sentences:
- Can they help him?
- They cannot help him.
- When you say 'cannot help' - it denotes impossibility- that cannot be done - impracticable .
- When you say 'may not help' - it shows improbability - that cannot be believed - something absurd
(V) to express a wish 'may' is used in formal English
- May God bless you!
- May success be yours!
(VI) 'Could' and might are past equivalent of 'can' and 'may':
- She could play chess when she was at college.
- The principal said, I could might take leave.
- We thought he might go abroad.
(VII) could expresses polite requests sometimes:
- Could you do me a favour ?
- Could you open the door, please?