—Do you know where David is? I couldn't find him anywhere.—Well. He ________have gone far—his coat's still here.
Was it because his mother was ill ______ he didn’t go to school?
Our teacher asked us to give all the used books to ______ needed them.
We have got plenty of time. We ______ hurry.
—Do you mind if I keep pets in the building? —______.
Can you see that building ______ by trees? That’s ______ we study.