if you listen to me, you______ have some candies as a reward,” the woman told her little son

Some people disagree with the idea _____ digital textbook will improve education quality while the traditional textbook is out of date

Was it in the library________he often went to do some reading________he met the pretty girl?[ ]

The chairman thought ________ necessary to invite Professor Smith to speak at the meeting.

His writing is so confusing that it’s difficult to make out ________ he is trying to express.