两台相同的泵串联后，其扬程变化是（）。A、H＝H1＋H2； B、H≥H1＋H2； C

Here are some facts about homes in the United States and the people who live in them. In the early 1990s, about 50% of the Americans own their homes and the rest rent(租) their homes. The rented homes are usually apartments(公寓).

74% of the people in the US make their homes in or around cities. 26% live in the country. Dogs live in about 40% of all homes in the US. About half that number have cats.

Families in the US are becoming smaller. On the average（平均）,2.64 people lived in a home in the early 1990s. In 1960, the average was 3.5.

Half of the teenagers in the US have their own bedrooms.

An American moves, on the average，twelve times in his or her life. In Japan, a person moves about five times, and in England a person moves eight times.

小题1:According to (根据) the passage ,where do most Americans live?

A．In the countries.

B．Around the farms.

C．In the towns near the sea.

D．In or around the cities.小题2: How many American families own a cat?

A．40%

B．26%

C．74%

D．20%小题3:Families in the US are              .

A．becoming bigger

B．becoming smaller

C．no change

D．not sure小题4:Do all the children in the US have their own bedrooms?

A．Yes, they do.

B．No. Half of them do.

C．No, 5% of the them do.

D．I don’t know.小题5:The passage is about _________________.

A．people and homes in the United States

B．dogs and cats in American homes

C．teenagers’ bedrooms

D．moving house

月球表面土壤里的—种非常有用的资源——可控核聚变的原料，关于的叙述正确的是

A．³He和⁴He是同种原子

B．³He和⁴He互为同位素

C．核聚变时，原子核发生了变化，发生了化学反应

D．在³He中存在：质子数＝中子数＝核外电子数

男性，54岁，类风湿关节炎(RA)病史5年，近2个月来感到双手指关节痛加重，晨僵约1小时，从未经过正规系统治疗。检查：双手第1、2MCP滑膜肥厚，右侧第2～4指近指关节肿胀，压痛明显，左侧第2、3指近指关节肿胀伴压痛，双手X线示双腕诸骨间隙消失并融合，双掌指、近指关节间隙明显狭窄。

下列哪项最有利于判断此病人病情活动性( )

A．类风湿因子

B．抗核抗体

C．C反应蛋白

D．C₃

E．免疫球蛋白

下列关于股动脉的描述哪项是正确的()

A．续于髂外动脉

B．外侧有股静脉伴行

C．内侧有股神经伴行

D．近端浅表有肌肉覆盖

E．是髂内动脉的直接延续

审核从不同角度分类，可分为（）。

A.手工审核和自动审核

B.有效性审核、一致性审核和分布审核

C.选择性审核和全面审核

D.数据收集时进行的审核和数据收集后进行的审核

E.热平台审核和冷平台审核