问题 单项选择题

根据影像获取的时间,可将放射性核素显像分为()

A.局部显像和全身显像

B.平面显像和断层显像

C.静态显像和动态显像

D.阴性显像和阳性显像

E.早期显像和晚期显像

答案

参考答案:E

单项选择题 A1/A2型题
阅读理解

阅读理解。

     When skateboarding started in the 1960s, skateboards were made of wood and had clay wheels. Since

the wheels did not grip concrete well, riders could do very few tricks with them. Soon people lost interest

in the sport.

     In 1973, though, a new wheel was invented in California. It was made of a plastic called urethane (氨基

甲酸酯). A skateboard with these wheels moved very quickly and it also gripped the concrete well. During

the next few years skateboards were further improved. The urethane was perfected, and because the boards

were shaped better, riders liked them better. These skateboards gave new life to skateboarding.

    The streets were not safe for skateboarding, although it was easy to ride on the streets. As a result,

skateboard parks sprang up. The first parks appeared in California and Florida. At first there were only outdoor

parks that had concrete slopes with small curves (曲线). Then more exciting parks appeared which had steep

downward slopes, banked curves, and vertical walls. Today, there are both indoor and outdoor parks.

     In most of these parks riders must wear helmets (头盔) as well as knee and elbow pads (护肘). This gear

can prevent a fall from causing serious injury.

     Whenever they ride, people should always use this safety equipment, and they should learn how to fall

safely. Many accidents happen during the first week of riding, so it is very important that riders be taught well.

1. Why were the new skateboards more popular? [ ]

A. They were safer than the older ones.

B. The older models were expensive.

C. They were stronger than the older ones.

D. People could do more tricks with them.

2. The underlined word "grip" in the first paragraph means "_____". [ ]

A. move over a surface without slipping

B. stick to

C. replace

D. break down

3. Skateboard parks developed because _____.[ ]

A. parents decided it would be a good idea

B. too many accidents happened on the streets

C. many streets did not allow skateboarding

D. most city parks did not allow skateboarding

4. Which of the following statements about skateboard parks is TRUE? [ ]

A. The first parks appeared in Scotland and Florida.

B. The earlier parks had steep slopes.

C. In the parks people don't have to wear helmets.

D. At first there weren't any indoor parks.