---This is _____ music I’ve told you about. Isn’t it beautiful? ---Yes, it’s great. I’ve never heard such____ beautiful music before.
Sometimes parents find ______ hard to communicate with their children.
Nowadays scientists are working hard to find out ______ to do with air pollution.
Good teachers can usually give the students______ advice on their study.
Chinese people have been using paper for over______ years.
Mother came into my study with a cup of milk in one of her hands, and an apple in ______.