At the meeting they discussed three dif-ferent_______to the study of mathematics。
I feel uncomfortable each time I remember the situation _____ Mary didn’t agree with me _____ the matter.
I want to buy that kind of cloth because I ________ the cloth_______ well.
______ the Internet is of great help, I don’t think it’s a good idea to spend too much time on it.
To keep healthy, Professor Johnson ______ cycling as a regular form of exercise after he retired.
Time should be made good use of ___ our lessons well.