问题 选择题

由于偏食,小王的上皮组织发生角化,皮肤粗糙,同时皮下血管出血,这是由于他体内缺乏(  )

①维生素A        ②维生素B       ③维生素C         ④维生素D.

A.①②

B.①③

C.②③

D.②④

答案

维生素的种类很多,对人体的作用很大.维生素A的作用是促进人体正常发育,增强抵抗力,维持人的正常视觉,缺乏时人体会患夜盲症,皮肤粗糙等症状;维生素C的作用是维持正常的新陈代谢,维持骨骼、肌肉和血液的正常生理作用,增强抵抗力,缺乏时会患坏血病,皮下、牙龈出血等.根据题中的叙述可以判断他体内缺乏维生素A和维生素C.

故选:B

单项选择题
阅读理解

阅读理解。

     If you do not use your arms or your legs for some time, they become weak; when you start

using them again, they slowly become strong again. Everybody knows this, and nobody would

think of questioning this fact.   1   When someone says that he has a good memory, he really

means that he keeps his memory in practice by exercising it regularly, either consciously or

unconsciously. When someone else says that his memory is poor, he really means that he does

not give it enough opportunity to become strong.  2   . One of them exercises his arms and legs

by playing tennis, while the other sits in a chair or a motor car all day.

     If a friend complains that his arms are weak, we know that it is his own fault. But if he tells us

that he has a poor memory, many of us think that his parents are to blame, or that he is just unlucky,

and few of us realize that it is just as much his own fault as if it was his arms or legs that were weak.

   3  . But all of us can, if we have ordinary bodies and brains, improve our strength and our memory

by the same means  practice.

     Have you ever noticed that people who cannot read or write usually have better memories than

those who can?  4   . Of course, because those who cannot read or write have to remember things.

They cannot write them down in a little notebook and they have to remember dates, time and prices,

names, songs and stories, so their memory is the whole time being exercised.

  5  .

A. What do you think of it?

B. Yet many people do not seem to know that the memory works in the same way.

C. Not all of us can become extremely strong or extremely clever.

D. So if you want a good memory, practice remembering.

E. Someone else says that he is poor in health.

F. Why is this?

G. The position is exactly the same as that of two people.