Question

Fill suitable modal auxiliary:

You think the children should be in bed on time. It's already 11 o'clock.
You say: 'It's time the children _______ be in bed.'

• A. shall
• B. will
• C. would
• D. must

Answer 1

The correct option is D must

Modal Verbs show us the attitude of the speaker to what is being said or done. The term "modal" means expressing mood and mood is a way to express the attitude of the speaker.

According to the meaning of the sentence it expects an extreme obligation

Option D is the correct answer because it expresses extreme obligation

Whereas option A expresses certainty in future action;

option B expresses the same as option A;

option C expresses uncertainty in future action and is the past form of "will"