He met many problems ________ he was going over his lessons. [ ]
Did the actor live alone in his house? —Yes. He has a wife and two children. But ____ of them lives with him.
Our classroom is very clean. Do you know who__cleaned it﹖
My father often brings me____, so I’m always happy when he comes back.
The art exhibition is really worth _______,and you’re sure to learn lot from it.