--- 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
Would you mind ______ those old jeans?
I have been skating _______ nine o’clock.
He _____ when the UFO arrived.
The teacher said that they ______ hard-working students.
His father _____ to Nanjing. He _____ back next week. A. has been, is B has been, will be C. has gone, is D. has gone, will be