Modals

Semi-auxiliary
Definition:
A multi-word construction based on an auxiliary verb and having some of the same grammatical characteristics. Also known as a semi-modal or a lexical auxiliary.Semi-auxiliaries include be about to, be able to, be going to, be likely to, be supposed to, had better, have to, ought to, used to, and would rather. Some are followed by an infinitive; others by a zeroinfinitive.
"Women have got to make the world safe for men since men have made it so darned unsafe for women."
"A great teacher is supposed to show them there are other points of view besides theirown."
"Only the first word in a semi-auxiliary is a true auxiliary, since only that word functions as an operator, for example in forming questions:
Is Sandra going to apply for the job?
Had I bettereat now?
Is Jennifer supposed to phone us today?
The semi-auxiliaries may come together to make a long string of verbs:
We seem to be going to have to keep on paying the full fee.
They are likelyto be about to start working on our project.
"Some of the semi-modals, like have to and be going to, can be marked for tense and person:
- past tense:
He had to call the police. (CONV)

-third-person agreement:
Maybe she has to grow up a bit more. (CONV)
These semi-modals can sometimes co-occur with a central modal verb or another semi-modal."
En esta página hay varios ejercicios de los4 temas:
http://www2.sdfi.edu.cn/netclass/jiaoan/2007/zongheyingyu/yufalianxi/Modals.htm

Modals, Semi-Modals, Modal Idioms, Semi-Auxiliaries and Catenatives
I. Write the three negative forms of“must”:
1. He must be on the sports ground.
2. He must get up at five.
3. He must park the car here.
II. Translate the following sentences and analyze the use of the modals:
1. Someone must havelost the game.
2. Someone had to lose the game.
3. You mustn’t come early.
4. You don’t have to come early.
5. You needn’t send me any money—I have some in hand.
6. You mustn’t send me any...