Hi,

My question is: I know it is wrong to say "I did not not kept it there" - it should be "did not keep". However, I do not know how to formulate/state the rule behind this. Could someone please help?

Thanks!

Hi Neha

Yes, I can help. In your example, "did" is the past form of the auxiliary verb "do" and most (but not all) auxiliaries are always followed by the plain (infinitive) form of the main verb (in this case, "keep"), even when it is combined with "not" to form a negative, or used to form a question.

I did keep it there. (not *I did kept it there).
I did not keep it there. (not *I did not kept it there.)
Did I keep it there? (not *I did not kept it there.)
Ed does like Tom. (not *Ed does likes Tom.)
Ed does not like Tom. (not *Ed does not likes Tom.)
Does Ed like Tom? (not *Does Ed likes Tom?)
I did go shopping yesterday. (not *I did went shopping yesterday.)
I did not go shopping yesterday. (not *I did not went shopping yesterday.)
Did I go shopping yesterday? (not *Did I went shopping yesterday.)

And the same applies with the modal auxiliary verbs, like "can" and "must:

Ed can keep it there. (not *Ed can keeps it there.)
Ed can't keep it there. (not *Ed can't keeps it there.)
Can Ed keep it there? (not *Can Ed keeps it there?)

Ed must keep it there. (not *Ed must keeps it there)
Ed must not keep it there. (not *Ed must not keeps it there)
Must Ed keep it there? (not *Must Ed keeps it there?)

Can you see that all the main verbs are in the plain form?

Does that help?

PaulM

* = ungrammatical

Hi Paul,

Yes, it does help :)

This is what I am currently looking at: In case of a Aux. Verb + Main Verb combination, the auxiliary takes on the tense and the regular verb stays in the base form for the following auxiliaries:

Primary Auxiliary: All forms of 'do' (but not applicable to forms of 'have' and 'be')
Modal Auxiliary: can/could, must/should, will/shall, may/might, would (unless the usage is one of these 9 auxiliaries + another auxiliary + main verb - e.g., Ed must have kept it there.)

Does this make sense to you?

Regards,
Neha

Hi Neha

Yes it does. Essentially, you have it right.

Auxiliary verbs are tensed, while the main verbs that follow them are non-tensed. But note that some auxiliaries, like "must", have no past tense form. So another way has to be found to express past tense, such as "Ed must have been on holiday" where the perfect tense indicates that it refers to past time.

But be careful when you say "9 auxiliaries + another auxiliary + main verb", because the modal auxiliaries, like "can" and "will" etc. cannot combine with other modals: you can’t say *He must can swim". But a modal auxiliary can of course combine with the non-modal auxiliary “have”, as we have seen in the “Ed” example above.

PaulM

Ah! That sounds like a complete explanation now. Thanks much Paul, appreciate the help!

Best,
Neha

Hello Neha,


I don't whether it is a rule or not but I noticed it always no two second form of verb are used for one activity and with one subject.
When you say did- second form, so the next verb must be in such singular form.

Must is not and auxiliary verb it's a model verb

Must - have to ( shows compulsion )
No model verb has past form.

Shall - should (not past of shall but a different model verb )

Hello Laddu,

You have made some mistakes in your post:

The verb that follows auxiliary "do" is always in the plain (base) form.


Modal verbs are auxiliary verbs, they are just a special kind.


.
That's wrong! 4 of the modal auxiliaries have a past form:
can~could, may~might, will~would, shall~should


Wrong, "should" is the past form of "shall"

PaulM

Hey Paul,

I am not surprised. Would you please answer some questions..????

You should take care of your parents. ( do you think this sentence is in past. )

G7E

Do (present)
did (past)
done (participle)

So if "should" is past form then where is the participle form.

PaulM