问题 单项选择题

马钱子炮制的最佳条件( )

A.温度200~210℃时间3~4min
B.温度210~220℃时间2~3min
C.温度220~230℃时间2~3min
D.温度230~240℃时间3~4min
E.温度240~250℃时间3~4min

答案

参考答案:D

解析: 研究指出:当温度在230~240℃和时间为3~4min时士的宁转化了10%~15%,马钱子碱转化了30%~35%,而此时土的宁和马钱子碱的异型和氮氧化合物含量最高。如果低于该炮制温度和少于该炮制时间,士的宁则不易转化成异型和氮氧化物,士的宁减少甚微;如高于该炮制温度和延长该炮制时间,士的宁、马钱子碱,连同生物碱的异型和氮氧化合物等马钱子中大部分成分将一同被破坏,因此,上述温度和时间是马钱子炮制的最佳条件。

阅读理解

阅读理解。

     What is a library for? Most libraries have books and other things to read. Many of them  have things

to listen to. Some libraries even have computers. Very few people would think of a library as a place to

live in.

     One library in New York City turned into (变成) a home for 250 people for a few days. These were

all people near the library. They slept on the floor. Why did the people move into the library?

     The people moved into the library because the city wanted to close it to save money. These 250 New Yorkers loved their library. They didn't want to lose it. So they moved in. They knew that the library couldn't be closed if they were living inside it. At last the city agreed to keep the library open, and the people all went home.

1. Where did the story happen______?     

A. In New York City.                

B. In a school in New York City.

C. In the streets in New York City.      

D. In most libraries in New York City.

2. The library had hundreds of ______.    

A. workers in it                      

B. policemen in it

C. people living in it                  

D. computers in it

3. The people in the story ______.    

A. were all the workers in the library    

B. were all people near the library

C. didn't read any books              

D. wanted to buy some computers

4. Why did 250 people move into the library? Because______.      

A. these people wanted to save money

B. these people needed places to live in

C. the library was very quiet

D. they loved the library and they didn't want to lose it

5. From the passage we know that ______. 

A. the library was kept open at last

B. the library was closed because no one read in it

C. the library became a home of these people

D. the city saved a lot of money

单项选择题