He tried his best to solve the problem, 　　　　difficult it was.

What do you suppose I should wear for the party? — Don’t bother to _____. Nobody will care about it.

always cold in Zhejiang in winter, but it ____ be warm at times.

I’m good at English,and I want to learn ____ foreign language.

下列加点词的用法不同其它三项的是