问题 单项选择题 A1/A2型题

药物质反应的半数有效量(ED50)是指药物()

A.与50%受体结合的剂量

B.引起最大效应50%的剂量

C.引起50%动物死亡的剂量

D.使50%动物无效的剂量

E.引起50%动物阳性反应的剂量

答案

参考答案:E

阅读理解

Weekends are important for us. We can relax ourselves. Do you know what Americans in the early twentieth century (1900~1925) did on weekends? What do you do on weekends now? In the early twentieth century, people spent lots of time at home on weekends. Then, new inventions changed the weekends.

*People used electric streetcars to travel in the cities. On weekends, they rode the streetcars to the parks. Young people like roller coasters.

* The first movie lasted only one minute. In the 1920s, movie theaters sold millions of tickets each week! In 1927, movies finally had sound. Sometimes people stayed at home and listened to another new invention —the radio.

* People in cities worked indoors during the weekdays, so they wanted to be outdoors on weekends. Bicycling became a popular activity.

* Now there are more inventions in our life. People have more time and money, too. So they have many ways to spend their weekends.

* People travel by their own cars. Or they can visit big parks like Disney World and ride modern roller coasters and go higher and faster than ever before. *

They can choose from lots of different movie theatres. Or they can watch videos at home.

* More and more people begin to do all kinds of sports at gym.

Others turn on their TV and watch sports on "Family Night".

小题1:Before 1927, __________.

A.people can watch videos at home

B.the movie had sound

C.People could go to the movie theatres to see movies

D.people could watch sports on "Family Night"小题2:Long time ago, people spent their weekends __________.

A.at home

B.in the theatres

C.outdoors

D.in Disney World小题3:Which is a popular activity in the early twentieth century?

A.Watching TV

B.Riding the electric streetcars

C.Listening to the radio

D.Bicycling小题4:The underlined word "lasted" means          .

A.began

B.was over

C.played

D.spoke小题5:Which is TRUE about the weekends in America?

A.They still see movies without sound now.

B.They didn't go outside in the early twentieth.

C.The weekends are not the same in different times.

D.They don't go to the parks any more now.

单项选择题 共用题干题