---- Have you been here before?---- This is the second time I ______to the Great Wall.
21. The children lost in the woods; otherwise, they would have been at the lakeside camp as scheduled.
Harry is feeling uncomfortable. He _____ too much at the party last night.
When I was a child, I ______ watch TV whenever I wanted to.
He ________ sleep, although he tried to, when he got on such a hunt for an idea until he had caught it.
--- You needn’t take an umbrella. It isn’t going to rain.--- Well, I don’t know. It do.