Auxiliary

A Auxiliary | Uses | Present/ future/ past/ not |
May | 1. Polite request | May you come please? |
| 2. Formal permission | MAY I go out tonight? |
| 3. Less than 50% certainty |May be go shopping tomorrow |
Might | 1. Less than 50% certainty | He might have been gone to Paris |
| 2. Polite request | Might I use your phone? |
Should | 1. Advice | You shoulddo your homework |
| 2. 90% certainty | I should call my parents. |
Ought to | 1. Advice | you ought not drink much beer |
| 2. 90% certainty | I ought to stay in bed on sunday. |Had better | 1. Strong advice with threat of bad result/ bad consequence | It is already late. We had better hurry. |
Be supposed to | 1. Expectation | I was supposed to go to the party |Must | 1. Strong necessity/ strong advice | You must have a passport to to travel abroad |
| 2. Prohibition (negative) | You mustn´t be late again |
| 3. 95% certainty | He muststudy more English |
Have to | 1. Necessity/ strong advice | I have to go to class everyday |
| 2. Lack of necessity (neg.) | She don´t have to work everday. |
Have got to | 1.Necessity/ strong advice (colloquial) | Drivers have got to get a license to drive a car |
Will (expresses less certainty) | 1. Espontaneous | It will rain next week. |
| 2. Polite request |Will you take me with you? |
| 3. Promise | I will call you back more afternoon |
Be going to (expresses more certainty) | 1. Intended 100% certainty | He is going to sleep in the night || 2. Definite plan (planned, premeditated) | I’m going to the cinema tomorrow |
Can | 1. Present ability/ possibility | He can cook |
| 2. Informal permission | Can you speak Chinese?|
| 3. Informal polite request | Can i borrow your book? |
| 4. Impossibility (negative only) | It can't be true |
Could | 1. Past ability | My grandfather could speak two...