问题 单项选择题

X线对比度是指

A.透过物体两部分的X线强度之比
B.透过物体两部分的X线强度之和
C.透过物体两部分的X线强度之差
D.透过物体两部分的X线强度之积
E.透过物体两部分的X线强度平方和

答案

参考答案:A

解析:X线对比度是指X线照射物体时,如果透过物体两部分的X线强度不同,就产生了X线对比度(Kx),也称射线对比度。

阅读理解

Mr .Brown got up late this morning. He was going to be late for work. It was raining hard and the streets were wet. He drove so fast that he didn't see the red lights. He couldn't stop his car and hit a car. An old man got out of the car and called out angrily, "What are you doing? How can you drive so fast?"

"l'm sorry ,sir," said Mr.brown, "l didn't see the lights turn red." Then he brought out a bottle of wine(酒) and gave it to the old man.

"It's cold today, sir," said Mr.Brown. "Please drink a little, and then you'll get warm."

The old man drank some wine and became happy. He asked, "l'm felling much better now. Why don't you drink any?"

"l can't drink anything now ,sir , "answered Mr.Brown "l'm waiting for the policeman .Only drunkards (酒鬼)cause(发生) accidents(事故) ,you know.

小题1:When did the story happen?

A.In the morning

B.In the afternoon

C.In the evening

D.At night小题2:Why did Mr.Brown drive so fast?

A.He was happy that day

B.He was good at driving

C.There were few cars in the street

D.He was afraid to be late小题3:Mr.Brown hit the car because of the following EXCEPT that ____.

A.he didn't see the red lights

B.he drove fast

C.he couldn't drive at all

D.it was raining hard小题4:Why did Mr.Brown give a bottle of wine to the old man?

A.To make him happy

B.To make him drunk (醉的)

C.To make him warm

D.To make friends with him小题5:We can know that _____ at last.

A.Mr.Brown was not late for work

B.the old man Mr.Brown became good friends

C.Mr.Brown drank some wine

D.Mr.Brown fooled the old man

问答题 简答题