有一串分数：$\frac{1}{1}$，$\frac{1}{2}$，$\frac{2}{2}$，$\frac{1}{2}$，$\frac{1}{3}$，$\frac{2}{3}$，$\frac{3}{3}$，$\frac{1}{3}$，$\frac{1}{4}$，$\frac{2}{4}$，$\frac{3}{4}$，$\frac{4}{4}$，$\frac{1}{4}$，$\frac{1}{5}$，$\frac{2}{5}$…，这串数的第400个数是几分之几？

高大山脉往往是地形区的分界，如太行山脉东西两侧就分别是

若以下四幅图分别表示广州、武汉、北京和哈尔滨中的一个，则④是（　　）

Subject: Can you help?            

From: Rose

Dear Knowledgeable,

    I have a good friend, Ann. She is very clever and can speak English really well. A very important English speech contest for our whole city will be held next month. Our classmates all think Ann is the best person to represent the class in the school contest and make sure she will win. But the problem is that she's very shy and that she's terrified of speaking in front of other people.

    She can't tell others about it, because she doesn't want to let her friends down. I can't think of any good advice to give her, but you always come up with good solutions to people's problems. Can you give us some good advice？Do you think we can tell the truth to the rest of the students?

Yours,

Rose