Read these sentences and choose the correct answer to fill in the gaps.
1. That's ridiculous- you ____ be joking.
can
must
2. It ____ be the postman; it's far too early.
mustn't
can't
3. I _____ do my homework.
Ответы
Ответ:
Correct answer 1: must
Correct answer 2: can't
Correct answer 3: must
Объяснение:
Modal verb 'can'
Can is an auxiliary verb, a modal auxiliary verb. We use can to:
- talk about possibility and ability
- make requests
- ask for or give permission
The main verb is always the bare infinitive (infinitive without "to").
subject
auxiliary verb
main verb
+
I
can
play
tennis.
-
He
cannot/can't
play
tennis.
?
Can
you
play
tennis.
Modal verb 'must'
We often use must to say that something is essential or necessary, for example:
Must is a modal auxiliary verb. It is followed by a main verb.
subject
auxiliary verb
main verb
I
must
go
home.
You
must
visit
us.
We
must
stop
now.
In general, must expresses personal obligation. Must expresses what the speaker thinks is necessary. Must is subjective.
In each of the above cases, the "obligation" is the opinion or idea of the person speaking. In fact, it is not a real obligation. It is not imposed from outside.