问题 单项选择题

关于房间隔缺损。

房间隔缺损患儿,出生时及婴儿早期易发生暂时性青紫的原因是

A.右心房压力大于左心房

B.右心血流量多

C.肺循环充血

D.体循环血流量减少

E.右心室压力增高

答案

参考答案:A

解析:出生后左房压高于右房,如存在房缺则出现左向右分流,分流量与缺损大小、两侧心房压力差及心室的顺应性有关。生后初期左、右心室壁厚度相似,顺应性也相近,故分流量不多。随年龄增长,肺血管阻力及右室压力下降,右心室壁较左心室壁薄,右心室充盈阻力也较左心室低,故分流量增加。由于右心血流量增加,舒张期负荷加重,故右心房、右心室增大。

阅读理解

阅读理解。

     Almost everyone likes dogs, and almost everyone likes to read about dogs. I have a friend. He has a big

police dog with the name Jack. Police dogs are very clever. Every Sunday afternoon my friend takes Jack

for a long walk in the park. Jack likes these long walks very much.  

     One Sunday afternoon a young man came to visit my friend. He stayed a long time. He talked and talked.

Soon it was time for my friend to take Jack for a walk. But the visitor still stayed. Jack became much worried.

He walked around the room several times and then sat down in front of the visitor and looked at him. But the

visitor paid no attention to Jack. He went on talking. At last Jack got angry. He went out of the room and came

back a few minutes later. He sat down again in front of the visitor, but this time he took the visitor's cap in his

mouth.

1. The young visitor stayed a long time in my friend's house, didn't he? [ ]

A. Yes, he was.

B. Yes, he did.

C. No, he wasn't.

D. No, he didn't.

2. Jack became worried because ______. [ ]

A. he wanted to go out for a walk 

B. he wanted to play with him    

C. he didn't know the young man  

D. he wanted to eat something

3. Jack sat down in front of the visitor because he wanted            . [ ]

A. the visitor to talk with him

B. to join the talk    

C. to show the visitor how clever he was

D. the visitor to leave the house soon

4. The visitor went on talking and ______. [ ]

A. he paid no attention to his cap

B. he didn't like Jack    

C. he paid no attention to Jack

D. he didn't know that his cap was taken away by Jack

5. At last Jack took ______ in his mouth. [ ]

A. food

B. nothing

C. the visitor's cap

D. the visitor's bag

单项选择题