How to put a
Modal Verb in Past
A Modal Verb has only one form. It cannot be used with a Gerund (…..ing), nor does it use an ‘..s’ for the third person singular. Except for ‘OUGHT TO’ it is not followed by a preposition. This is the full list:
02
This is the easy part! This is the formula:
MODAL+HAVE+PAST PARTICIPLE
Here is no NEEDN’T, HAVE TO or HAD BETTER. ‘Have to’, which uses the auxiliary ‘DO’ is NOT a Modal Verb with this definition (There is no ‘correct’ definition of a Modal Verb.
In the same way that we use modal verbs to say how certain we are about things in the present we can also use them to speculate about the past.
Can't, could, should, ought to, must, will, won't, might, may, would
SHOULD
OUGHT TO
MUST n’t
WILL
WON’T
MIGHT
MAY
WOULD