问题 选择题
若i为虚数单位,则复数z=
2-i
2+i
在复平面内对应的点所在象限为(  )
A.第一象限B.第二象限C.第三象限D.第四象限
答案

复数z=

2-i
2+i
=
(2-i)2
(2+i)(2-i)
=
3-4i
5
=
3
5
-
4
5
i,它在复平面内对应的点的坐标为(
3
5
,-
4
5
),

故选D.

阅读理解

No one knows how man learned to make words. Perhaps he began by making sounds like those made by animals. Perhaps he grunted like a pig when he lifted something heavy. Perhaps he made sounds like those he heard all round him—water splashing, bees humming, a stone falling to the ground. Somehow he learned to make words. As the centuries went by, he made more and more new words. This is what we mean by language.

People living in different countries made different kinds of words. Today there are about fifteen hundred different languages in the world. Each containsfour or five hundred thousand words. But we do not need all these. Only a few thousand words are used in everyday life. The words you know are called your vocabulary. You should try to make your vocabulary larger. Read as many books as you can. There are plenty of books written in easy language. Your dictionary is your most useful book.

小题1: What do we mean by language?

A.Sounds made by man.

B.All the words made by man.

C.Different kinds of sound.

D.The way man learns.小题2: Form the passage we know that long long ago________.

A.no one learned how to make sounds or words

B.animals taught man to learn the language

C.man learned the language by lifting heavy things, falling to the ground,and so on

D.man followed a lot of things in nature to make sounds and words小题3: What is the number of languages spoken in the world today?

A.500.

B.5,000.

C.1,500.

D.15,000.小题4:In which sentence can the word "contain(s)" be put so that it is a right one?

A.I________ several dictionaries.

B.Sea water________ salt.

C.A dog _______ four legs.

D.Mr. Smith _____ glasses on his nose.小题5: Which of the followings is the best if we want to make our vocabulary larger?

A.To read more books.

B.To use the words in everyday life.

C.To use the words in class.

D.To write the words.

问答题