You should let your children play ______ you can see them.
Must I wait till you come back? No, you ______.
It is in the school ______ he studied ten years ago ______ he gave a wonderful speech.
I don't think she ____what happens to her children.
____ touch anything unless your teacher tells you to
He has a great interest in ______ history, especially ______ history of the Tang Dynasty.