在通常情况下，海相沉积中的水比陆相沉积中的水矿化度低。

Chinatown is the name given to an area in the middle of London. It is just between Leicester Square and Shaftsbury Avenue. Gerrard Street is at the center and is the most important street in the area. There is a large Chinese community(社区) with a lot of Chinese restaurants, Chinese supermarkets and shops in this street.

In the 1950s, it was a poor area and everything was very cheap. At the same time, the world rice market changed and thousand of farm workers in Hong Kong lost their jobs. They began arriving in London to look for work. They found jobs in the restaurants in this area. Many British people like Chinese food, and the restaurants were popular.

These restaurant workers often worked 17 hours a day and had no time to learn English. As more Chinese arrived, more shops and businesses grew up. Wives came and joined their husbands and children came and joined their fathers. The community grew, and Chinatown was born.

In the 1970s and 1980s, British-born Chinese started to have a better education and this brought economic(经济的) success to the area. Many families moved out of Chinatown, and there was more space for businesses. Gerrard Street become a street only for visitors and was soon a popular place for tourists.

Now everyone knows about London’s Chinatown. During the Chinese New Year, the streets are seen with flags and thousands of Chinese go into the streets. For most of the year, though, Londoners and tourists go there mainly for the food in the Chinese restaurants. They best restaurants are the ones where the Chinese eat.

小题1:Is this Chinatown in the middle of London?

小题2: Ws the area rich or poor in the 1950s?

小题3:Why did the restaurant workers have not time to learn English?

小题4:When did British-born Chinese start to have a better education?

小题5:What are the main points about Chinatown in this passage?

作用在同一点的三个力，大小分别为25N﹑15N﹑9N，它们的合力不可能的是（　　）

A．0N

B．49N

C．15N

D．1N

以下关于N1乙酰胆碱受体拮抗剂的叙述，正确的是

A．N1乙酰胆碱受体拮抗剂又称为神经节阻断药

B．属非去极化竞争性拮抗剂

C．在交感和副交感神经节能选择性地占据N1受体控制的离子通道或与N1受体结合

D．该类药物包括美加明(Mecamy-lamine)、樟磺咪芬(Trimetaphan Camsylate)等

E．主要用于治疗高血压

基础资料只能手工录入。（）

宋代，学士院移文于三省、枢密院，称（）；元代，中书省发文行省，称（）；明代，六部之间，及六部行都指挥使司，均用（）。