--- Look! It ____ be Jack on the playground.---It ____ be him. Because I saw him enter the school library just now.A. may; mustn’t B. must; can’t C. can; can’t
They are going to have a picnic _______ next week.
There are about ________ students in our school.
—Do you like our English teacher? —Yes. I think his class is very ________.
This is your pencil. ________ is over there, on the desk.
Doing morning exercises is good ________ our health.