土地登记的实质是( )。A．权利的保护 B．公示 C．公告 D．登记备案

阅读短文，然后根据短文内容选择最佳答案。

    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. ______ has a very very old car. [ ]

A. Mrs. Hill

B. Mrs. Bates

C. Mike

D. Joe

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. colorless pictures

C. colorful pictures

D. pictures with only a few colors

5. The writer thinks             . [ ]

A. his grandfather's idea 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

慢性肾功能衰竭最常见的诱因是

A．感染

B．劳累

C．应用肾毒性药物

D．饮食中蛋白质过量

E．有效循环血量减少

张教授在对口腔医生进行上岗培训时，指出口腔医务人员发生口腔临床感染的主要危险来自于（）

A.被污染器械刺伤

B.操作后不洗手

C.空气传播

D.接触血液及唾液

E.高速手机的飞沫

主汽阀阀座与阀壳的配合过盈量为（）。

A.0---0.05mm

B.0.10---0.20mm

C.0.25---0.35mm

D.0.40---0.45mm

求微分方程y"+4y=3|sinx|在[-π，π]上满足条件

的特解，