问题 名词解释

代谢饱和

答案

参考答案:

当毒物达到一定水平时,其代谢过程中所需要的基质可能被耗尽,或者参与代谢的酶的催化能力不能满足其需要,这样单位时间内的代谢产物量就不再随毒物浓度升高而增大,这种代谢途径被饱和的现象成为代谢饱和。

阅读理解

Tom walked into a shop . It had a sign outside : "Second-hand (旧的) clothes bought and sold . "He was carrying an old pair of trousers and asked the owner of the shop, "How much will you give me for these?" The man looked at them and then said: "Two dollars."

  "What !" said Tom. "I had guessed they were worth at least five dollars."

  "No," said the man, "they aren't worth a cent more than two dollars."

  "Well," said Tom, taking two dollars out of his pocket. "Here's your money. These trousers were hanging outside your shop. The list price (标价)of them was six dollars and a half. But I thought that was too much money, so I wanted to find out how much they were really worth."

  Then he walked out of the shop with the pair of trousers and disappeared before the shop owner could think of anything to say .

小题1:At first the owner of the shop thought that Tom __________.

A.wanted to steal the trousers   

B.wanted to sell the trousers

C.wanted to fool him      

D.wanted to buy the trousers小题2:The owner of the shop_______  for the old trousers.

A.would give Tom two dollars 

B.would pay three dollars

C.would pay five dollars      

D.would give Tom six dollars and a half小题3:The shop owner insisted(坚持) that the trousers were worth only two dollars because ____.

A.he wanted to sell them cheaply  

B.he wanted to buy them cheaply

C.he didn't like the trousers  

D.they were old and dirty小题4:In fact, the trousers _________.

A.were hanging inside the shop   

B.were stolen by Tom from the shop

C.had been the shop owner's    

D.had been Tom's小题5:From the story we know that _________ cheaper than the list price.

A.the owner sold the trousers two dollars

B.Tom sold the trousers one dollar and a half

C.the owner bought the trousers three dollars

D.Tom bought the trousers four dollars and a half

判断题