脑卒中的常见病因包括（） A.病毒感染 B.颅脑外伤 C.脑血管畸形 D.感染性心内

阅读理解。

     One day, Tomas Jefferson, the president of the USA, was crossing a river with a group of travelers.

The river was overflowing its banks. So it was very dangerous to cross it on a horse. Each man was

fighting for his life! Then another traveler came and he wanted to cross it, too. But he didn't have a horse.

He watched the group and then asked Jefferson to take him. Jefferson agreed immediately. The man climbed

on. After they were both safe to the other side of the river, someone asked the man,"Why did you ask

present for help? Did you know him?" The man was shocked because he didn't know Jefferson was the

president. "All I know," he said, "on some of your faces were written the answer NO, but there was the

answer YES on his face."

1. Who was Tomas Jefferson?

A. He was a businessman.

B. He was a teacher.

C. He was a captain.

D. He was the president of the USA.

2. How did they cross the river?

A. In a boat.

B. On their horses.

C. By swimming.

D. By building a bridge.

3. When the group were crossing the river, _________.

A. water was flowing out of the river

B. it was windy and very cold

C. there were many empty boats in the river

D. everyone wrote a word on the face

4. At last, _________.

A. both Jefferson and the man were safe to cross the river

B. only Jefferson crossed the river

C. only the man crossed the river

D. Jefferson's horse died

5. From the passage, we know that _________.

A. all the travelers were kind

B. Jefferson was helpful

C. nobody knew the president

D. the man gave Jefferson some money

一个正方形的边长为a，则比它的面积大b的长方形的面积为______．

恒生股票价格指数包括从中国香港500多家上市公司中挑选出来的( )家有代表性且经济实力雄厚的大公司股票作为成份股。

A．100

B．50

C．35

D．33

电压互感器用（）标志。

A、PA

B、PV

C、TA

D、TV

强度是材料受外力作用而不破坏或不产生塑性变形的能力。（）