The stronger the _____is, the more quickly a man will learn a new skill. In other words, it is up to whether he has an interest in it.

 Who would you rather ______ with the teacher about the problem?

(2014·江苏省三校4月阶段性考试)To their disappointment，Dr Wang gave a speech about the economy without even a passing________to the problem of unemployment.

It is reported that in our country cities ________ heavy air pollution that is 30 percent above the national standard or higher should try to meet standards by 2030.

I wasn’t complaining. I         expressed my surprise because I had never seen this happen in that case before.