Question

　　In 1931, it was discovered that some unknown substance present only in certain foods was necessary for good health. This substance was what is now called “Vitamin A”.

　　Vitamin A's biggest job is to keep the eyes going. Without it, people and animals get “night blindness” and eye problems. Lack of Vitamin A for a long time can even cause total blindness, particularly among children. This had a chance to be tested in Denmark during World Was I. Because of food shortage, many children had to eat man-made butter and skim milk（脱脂奶）, which contains no Vitamin A. Soon, they developed eye diseases. It was after they were given real butter and whole milk that they had no eye problems.

　　After Vitamin A was discovered, it took more than thirty years of experiments for scientists to be able to get a small amount of pure Vitamin A. Vitamin A is manufactured and is used successfully to treat a number of diseases. You can easily get enough Vitamin A by eating a variety of food. Good sources of Vitamin A are liver（肝脏） from some animals and dairy products such as milk and cream. Not only many vegetables contain carotene（胡萝卜素）, from which your liver can make its own Vitamin A, some fruits also provide carotene which helps your liver to supply Vitamin A. As long as you are getting Vitamin A from food you won't need to take any extra in the form of liquid or pills.

(1)According to the passage, if Vitamin A is not provided enough, which of the following are likely to be affected most se riously?

[　　]

A．Adults.

B．Animals

C．Children.

D．Plants.

(2) Vitamin A is a very. important substance mainly because it _______.

[　　]

A．is hard to made

B．helps to keep one's eyes healthy

C．can make butter more delicious

D．can not be produced in large quantity

(3) What made the children in Denmark get eye diseases during World War I?

[　　]

A．The war they experienced.

B．Their poor housing conditions.

C．The experiments on food.

D．The lack of Vitamin A in their food.

(4) According to the text, the following are all good sources of Vitamin A except _______.

[　　]

A．animal liver

B．flour

C．vegetables

D．milk

(5) Which of the following could be the best title of the passage?

[　　]

A．The Discovery of Vitamin A.

B．Some Unknown Substance.

C．Sources for Vitamin A.

D．Vitamin A.

Answer 1

答案：C;B;D;B;D
解析：

1. C  由第二段的“Lack of Vitamin A for a long time can even cause total blindness, particularly among children.” 2. B  由第二段中的第一句可知。 3. D  由第二段可得知。 4. B  由第三自然段，可知维生素A来自动物的肝脏、奶制品、蔬菜和水果，未提到粮食，利用排除法，故选B项。 5.D  该题为主旨大意题。短文从头到尾都是谈Vitamin A。因此D为最佳选项。