单工、半双工及全双工通信方式是按什么标准分类的？解释他们的工作方式。

课外阅读显身手。

　　今年春天，姥姥给了我一片仙人掌。当时它连根都没有，扁扁的满身是刺，我心想它能活吗？

　　回到家里，我把仙人掌随便往花盆的土里一插，浇点水，就不管了。过了一个星期，无意中我发现在它的顶端钻出一个嫩芽，它居然活了。

　　天气渐渐热了，太阳火辣辣的，仙人掌在阳光的炙烤下，就是几天不浇水，也依然那样青翠。

　　秋天，我把一片蟹爪莲嫁接在仙人掌上。过了些日子，蟹爪莲活了，枝叶逐渐茂盛起来。

　　冬天到了，蟹爪莲伫立在仙人掌上面，长势很旺。不久蟹爪莲开花了。密密层层的绿叶，衬着紫红色的花朵，充满了生机。但是，仙人掌由碧绿渐渐变黄，刺儿渐渐少了，它把营养输送给蟹爪莲，使蟹爪莲花繁叶茂。

　　我想，人们在欣赏美丽的蟹爪莲的时候，是不应该忘记仙人掌的。

1．“茂盛”的“盛”读音是____，它还有一个读音是____，组词________。

2．在“（　）”里填上适当的关联词语。

（　　）仙人掌把营养输送给蟹爪莲，（　　）它由碧绿渐渐变黄，刺儿也渐渐少了。

3．第2、3自然段写出了仙人掌的什么特点？

____________________________________________________________

4．人们在欣赏蟹爪莲的时候，不应该忘记__________________________的功劳。

5．本文赞美了仙人掌_____________________的精神。

阅读理解。

    There are many kinds of cars in this world. My grandfather thinks this is because cars are like their

drivers. He says, "Rich people have expensive cars, big people have large cars, and old people drive old

cars." But I don't agree with him. 

     My neighbor, Mrs. Hill, is 82 years old. She drives only on Tuesday, and then she drives only to the

bank. She never drives more than 30 kilometers an hour. Do you think Mrs. Hill has a very old and small

car? No! Her car is new. It's very large, and it can go 200 kilometers an hour!

     My friend Mike is an artist. He paints beautiful pictures with lots of colors. But his car is black.

Mrs. Bates has a very, very old car. It often has some trouble. Does she drive that kind of car because

she is poor? No, she has four restaurants and two million dollars in the bank. My uncle Joe has a very

small car. Every Sunday, he drives to the country with his wife, his three children, his mother and his dog.

    Now, you have read about my friends and their cars. Do you agree with my grandfather? Maybe you

have a car. Does it say something about you?

1. The writer's grandfather thinks ___. [ ]

A．a person has the same kind of car as himself (herself)

B．different people have cars of the same kind

C．poor people have large cars

D．artists have black cars

2. Mrs. Bates has an old car ___.[ ]

A．because she is poor

B．because she is rich

C．because she likes old cars

D．and the passage doesn't tell us why

3. Though Uncle Joe has a very small car, ___. [ ]

A．he has a dog

B．he has a large family

C．he has no children

D．he has few members in his family

4. The writer's friend Mike paints ___. [ ]

A．pictures in black

B．colorful pictures

C．colorless pictures

D．pictures with only a few colors

5. The writer thinks ___. [ ]

A．his grandfather's idea about cars is right

B．cars are often the same as their drivers in many ways

C．artists shouldn't drive black cars

D．a car doesn't say anything about its owner

根据现代统计学的研究成果，“关键的事情总是少数，一般的事情常常是多数。”这意味着管理工作最应该重视：( )

A．灵活、及时、适度

B．客观、精确、具体

C．突出重点，强调例外

D．协调计划和组织工作

在考虑所得税因素以后，实体营业现金净流量的公式有( )。

A．营业现金流量=息税前营业利润(1-税率)+折旧与摊销

B．营业现金流量=收入×(1-税率)-付现经营成本×(1-税率)+折旧与摊销×税率

C．营业现金流量=息后税后净利润+折旧与摊销

D．营业现金流量=营业收入-付现经营成本-息税前营业利润所得税

计算机网络按使用范围划分为：（）

A.广域网和局域网

B.专用网和公用网

C.低速网和高速网

D.部门网和公用网