When we were young, every evening my brother and I _____stay at home waiting for our mother to come back from work.

—Where did you get this book?—I picked it up from a second­hand bookshop if you ________ know.

 －Must I go and get some water now?   －No, you __________.

We can hardly believe such a young boy ______ travel around the world all by himself.

—What do you think people can do for their aged parents?—They_________ do anything except to be with them and be themselves.