简述心脏的主要功能以及其内部4个腔室的名称。

阅读理解。

     When George's car stopped at the traffic lights he couldn't start it again. The cars behind began to sound

their horns (喇叭), and the drivers began to shout. George got out of his car and pushed his car to the side

of the road.

     A young man and his girlfriend were standing nearby, "Excuse me," said George, "do you know anything

about cars."

     Before the girl could say anything, her boyfriend said, "Leave it me," Then he opened the bonnet at the

front of the car, "Oh, dear, it looks very bad." He shook his head and whistled (吹口哨)."

     George was a little surprised, saying, " In fact,… er. …The engine (发动机) is at the back."

     "Oh," said the young man. "it's a foreign car. Then I can't help you."

     "Can I have a look now?" asked the girl politely.

     She took the cover off the engine at the back of the car, asked George for his kit (工具箱), and worked

for five minutes, The car started at once.

     "Thank you." said George. "Can I give you a lift anywhere."

     "Yes," said the girl. "To the library, I'm going to get him a book about cars."

1. George's car broke down ______.

A. in front of the traffic lights

B. at a bus shop

C. by the side of the road

D. on his way to the library

2. It was clear that the young man-______.

A. wanted to learn how to repair cars

B. wanted to show off before his girl friend

C. thought the car couldn't be repaired

D. knew how to repair foreign cars

3. George was surprised because ______.

A. the young man instead of the girl offered to help

B. the young man said, "It looks very bad."

C. the young man opened the wrong part of the car

D. the young man shook his head and whistled

4. The girl ______.

A. was angry with the driver

B. was proud of her boy-friend

C. knew something about cars

D. hated her boy-friend

5. "Bonnet" most probably means the ______.

A. back

B. seat

C. car

D. cover

----How do you improve your listening skill, Mary?

----I often do it _______ tapes and English radios.

A．by hearing

B．in listening to

C．by listening to

D．for listening

出口企业办理增值税出口退税时，必须提供购进出口货物的增值税专用发票(税款抵扣联)，如果企业在购进货物时只取得了普通发票而未取得增值税专用发票，当该购进货物出口时，税务机关不予办理出口退税。 ( )

呼吸衰竭的发病机制主要有（）

A.肺泡通气不足

B.肺内动静脉解剖分流增加

C.酸碱平衡失调

D.V／Q比例失调

E.弥散功能减退

对重型肝炎的判断下列哪项最重要（）

A.ALT>500U／L

B.总胆红素>171μmol／L

C.PTA<40％

D.电解质紊乱

E.WBC15×10⁹／L