在国际金本位下，价格-现金流动机制对国际收支的调节作用较强。

Everyone needs friends. We all like to feel close to someone. It is nice to have a friend to talk, laugh, and do things with. Surely, there are times when we need to be alone. We don’t always want people around. But we would feel lonely if we never had a friend.

No two people are just the same. Sometimes friends don’t get along well. That doesn’t  mean that they no longer like each other. Most of the time they will make up and go on being friends. Sometimes friends move away. Then we feel very sad. We miss them very much. But we call them and write to them. It could be that we would even see them again. And we can make new friends. It is surprising to find out how much we like new people when we get to know them. Families sometimes name their children after a close friend. Many places are named after men and women who have been friendly to people in a town. Some libraries are named this way. So are some schools. We think of these people when we go to these places. There’s more good news for people who have friends. They live longer than people who don’t. Why? It could be that they are happier. Being happy helps you stay well. Or it could be just knowing that someone cares. If someone cares about you, you take better care of yourself.

小题1:The first paragraph tells us ________.

A．none needs friends

B．we always need friends around us

C．making friends is the need in people’s life

D．we need to be alone.小题2:Which of the following is what the writer doesn’t say in the passage?

A．People are not happy when their friends have them

B．People will never see their friends after their friends move away.

C．People can know their friends in different ways.

D．People like their friends very much if they get to know them.小题3:People who have friends live longer than people who don’t because ________

A．they feel happier and are healthy

B．they get a lot of help from their friends

C．they take better care of themselves

D．both A and C小题4:The main idea of this passage is ________.

A．that people are all friends

B．that people need friends

C．how to get to know friends

D．how to name a place

取100 mL 0.3 mol/L的硫酸和300 mL 0.25 mol/L的硫酸注入500 mL容量瓶中，加水稀释至刻度线，该混合溶液中H^＋的物质的量浓度是(　　)

A．0.21 mol/L

B．0.42 mol/L

C．0.56 mol/L

D．0.26 mol/L

宫腔容量为：

A．3ml

B．5ml

C．7ml

D．9ml

E．10ml

为防止食品发生酶促褐变，我们一般采用的方法有（）、（）、（）、（）。