It is obvious that on no account _____ to the teacher that he has done the homework on his own.

In China, _______ date 2013-1-4 has a similar pronunciation to “love you for a lifetime”, making it a most lucky and romantic day.

John sings very well. We listened to sing a beautiful song yesterday.

Would you like ______ to drink?

The air in Lanzhou is getting much _____ now than a few years ago .