What is the different between modal verb and auxilary verb?

[vichea]

Hello friends, i think that my grammer so poor,therefore, i need 2 hear from ur suggestion about the different of modal verb and auxilary verb. Thank in advance.

[ratanaros]

Auxiliary verbs are of three kinds.
1. Pricipal auxiliaries: to be, to have , to do
2. Modal auxiliaries (modals):can/could, may/might, must, ought, should/shall, will/would.
3. Semi-modals: to dare, to need, used

So i answer number one and number two.
1. We use the auxiliary do with negatives and interrogative form.
    We use the auxiliaries be and have with the present of past participle of ordinary verbs.
Ex, I am here. Ex. Yesterday, I was here.

2. I can not give the definition of modals. But i give you some tips of its using.
    - Modal can not use in continous and perfect tenses.
    - It can use with question form

Above answers, i think that is not enough for you. So pls check grammar books.


Ros Ratana

[Sarath]

A modal verb (also modal, modal auxiliary verb, modal auxiliary) is a type of auxiliary verb that is used to indicate modality  A modal verb such as would has several varying functions; it can be used, for example, to help verbs express ideas about the past, the present and the future. It is therefore wrong to simply believe that "would is the past of will": it is many other things.

A few basic grammatical rules applying to modal verbs

 Modal verbs are NEVER used with other auxiliary verbs such as do, does, did etc. The negative is formed simply by adding "not" after the verb; questions are formed by inversion of the verb and subject:

You should not do that.

Could you pick me up when I've finished?

 Modal verbs NEVER change form: you can never add an "-s" or "-ed", for example.

 Modal verbs are NEVER followed by to, with the exception of ought to.