问题 单项选择题

可增强心肌收缩力及明显舒张肾血管的药物是

A.肾上腺素

B.麻黄碱

C.甲氧明

D.多巴胺

E.去甲肾上腺素

答案

参考答案:D

解析:
多巴胺可激动α、β和外周的多巴胺受体。多巴胺在低浓度时作用于肾脏D1受体,舒张肾血管,使肾血流量增加,肾小球的滤过率也增加。高浓度(每分20μg/kg)的多巴胺可作用于心脏β1受体,使心肌收缩力加强,心排出量增加。

配伍题 B型题
阅读理解

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第二部分:阅读理解(共25小题,每题2分,满分50分)

第一节选择题(共20小题,每题2分,满分40分)

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

Getting around in Canada is fairly easy. Most cities have urban transportation systems, including buses, streetcars, and trains, and some of the larger cities also have subways. You can board these systems at regular stops along their routes. Some let you pay with cash while others require tickets. If you don’t have a ticket for the bus, you must pay with the correct amount of money. This is because the driver does not carry any change. If you plan to stay in a city for a long time, you may want to buy a monthly pass or a package of tickets to save money. You can buy subway tickets at any subway station.

If you have to take several buses or subways for a single trip, you do not need to pay money each time. Simply ask the driver for a transfer (换乘) ticket, or take one from the machines on the subway platform.

If you are not sure where to board the bus or the streetcar, just ask someone or follow the crowd. People can usually only board at the front of the bus where you show your pass to the driver. When using public transportation, Canadians line up. First come, first serve, is a common approach to many activities in Canada, and it is considered to be extremely rude to cut in any line.

Maps of routes and schedules are usually available from the public transit (运输) company in your area, and there is also a telephone information line. You may ask someone for the name of the transit company in your area, and then look it up in the telephone book.

46. What is this passage mainly about?

A. How to use public transportation in Canada.

B. How to save money when traveling.

C. Where to find subways in larger cities.

D. How public transit companies work.

47. If you pay the bus fare in cash, _____.

A. you may be given some change

B. you can exchange money with the driver

C. it might cost you a little more

D. you must have the exact amount of money

48. By buying a monthly pass or a package of tickets, you can ______.

A. take a bus whenever you want      B. go wherever you like

C. save money                     D. find comfortable seats

49. If you have to change subway lines on a single trip, _____.

A. you have to pay each time

B. you should buy another ticket from the machine

C. you must ask for the driver’s permission

D. you just need to pay once