问题 选择题
已知a2+b2=6ab且a>b>0,则
a+b
a-b
的值为(  )
A.
2
B.±
2
C.2D.±2
答案

∵a2+b2=6ab,

∴(a+b)2=8ab,(a-b)2=4ab,

∴(

a+b
a-b
2=
8ab
4ab
=2,

又∵a>b>0,

a+b
a-b
=
2

故选A.

选择题
阅读理解

阅读理解。

   There are thousands of products of all colors and shapes in a supermarket,making you believe that they

are worth a try.How? Packaging (包装) is the silent but persuading salesman.

   There on the shelves,each bottle,can,box,and jar has been carefully designed and measured to speak to

the inner self of  the consumer (消费者), because he is buying not only a product but also his belief in life.

Scientists  have studied consumer  behavior recently and  found  that  the look of the package has a great

effect on the "quality"  of the product and on how well it sells,because "Consumers  generally  cannot tell

between a product and its package. Many products are packages and many packages are products",as

Louis Cheskin,the first social scientist studying consumers' feelings for packaging,noticed.

   Colors are one of the best tools in packaging.Studies of eye movement have shown that colors draw

human attention quickly.Take V8 for example.For many years,the bright red color of tomatoes and carrots on the thin bottle makes you feel that it is very good for your body.And the word "green" today can keep

food prices going up.

   Shapes are another attraction.Circles often suggest happiness and peacefulness,because these shapes are pleasing to both the eye and the heart.That's why the round yellow M signs of McDonald's are inviting to

both young and old.

   This new consumer response  (反应)  to the colors and shapes of  packages  reminds  producers and

sellers that people buy to satisfy both body and soul.

1.According to the passage, ________ seems to be able to persuade a consumer to buy the product.

A.the pleasing color of the package

B.the special taste of the product

C.the strange shape of the package

D.the belief in the product

2.If a package or a product is round in shape,it can ________.

A.bring excitement to the consumers

B.attract the consumers' attention

C.catch the eye movement of the consumers

D.produce a happy and peaceful feeling

3."And the word 'green' today can keep food prices going up." This sentence suggests that consumers

today are ________.

A.starting to notice the importance of new food

B.enjoying the beauty of nature more than before

C.beginning to like green vegetables

D.paying more attention to their health

4.It can be inferred from the passage that V8 is a kind of ________.

A.vegetable dish  

B.healthy juice

C.iced drink  

D.red vegetable