－Why did you talk to the teacher after class?－I didn’t understand______________ during the lecture.

If I don’t buy them, _____ will buy them.

Do you often get online— Yes, I lots of time surfing on the Internet. It’s a goodway to relax.

We must work hard and make _______continuous progress so that we can make _______great contribution to ourcountry in the future

The boy has _______ questions to ask his teacher in every class.