同学们梳理了教材中与压强知识相关的实验，如图所示，其中分析正确的是（　　）

根据句意，用括号内所给单词的适当形式填空。
____ The maths problem is so difficult that few of the students can work it out_______ (easy).
____ Jim is a brave man. He always tells_________ (he) to calm down when he meets trouble.
____ Very few of people believe what the boy says because he is_________ (honest).
____ Everyone was very happy because of the famous writer’s _________ (arrive).
____ In the film, the soldiers were excited when they got their________(wife) letters.

下图为等值线，已知a>b>0，读图回答下列各题。