—You look tired, Jack． What's wrong with you?—Oh, 1 worked quite late last night． Nothing wrong with me,       ．

It is generally considered unwise to give a child ________ he or she wants.

 I have a tight budget for the trip，so I'm not going to fly ________ the airlines lower ticket prices.(2012·上海，32)

It is uncertain ___ side effects these weight-loss drugs will bring about, although hundreds of thousands of patients have taken it. 

_______ travelling expenses rising a lot, we had to change all our plans for the tour．