先化简,再求值:(1)(2a+1-1a-1)÷aa2-1,其中a=2.(2)(a

题型:解答题

问题:

先化简,再求值:
(1)(
2
a+1
-
1
a-1
a
a2-1
,其中a=2.
(2)(
a+2
1-a2
-
2
a+1
a
1-a
,其中a=
3
-1

(3)(
x2+4
x
-4)÷
x2-4
x2+2x
,其中x=-1.
(4)(1-
1
x+3
)÷
x2-4
x2+3x
,其中x=6.
(5)
x-2
x2-1
÷
2x+2
x2+2x+1
+
1
x-1
,其中x=
2
+1
. 
(6)(
x2
x-2
+
4
2-x
1
x2+2x
,其中x=
2

(7)(
1
a-b
+
1
b+a
)
÷
ab
a+b
.其中a=
2
+1,b=
2

(8)
x2+4x+4
x+2
÷(x2+2x)
,其中 x=
2
考点:分式的加减乘除混合运算及分式的化简
题型:解答题

阅读理解。

     An old woman from the United States is helping develop a small Chinese village. She lived there when

she was a child.

     In the early 20th century, Eunice Moe Brokck's parents came to Shandong Province and they gave birth

to her there. As she grew up, Brock saw the poverty (贫困), illness and war in China. So when she left China

at the age of 13, she decided to come back to help the poor people there.

     After her husband died, the old woman sold her house, her car, her forest and other things and moved to

China in 1999. She lived in Liumiao Village in Liaocheng of Shandong Province to help the villagers there.

     Though she is now in her nineties, she is still busy helping them. In the past few years Brock built a

computer room for the village school with her own money, and bought desks, chairs and books for students.

She also has been trying to improve the medical care conditions in a number of villages. In Liumiao, every

child can play with toys in Brock's home. At Christmas she always buys a lot of candies and takes them to

schools for students.  

     "I'm an American, but I love China," she said.

1. Eunice Moe Brock was born _________.

A. in Shandong Province

B. in the United States

C. in the south of China

2. Brock returned to China _________ years ago.

A. nine

B. thirteen

C. twenty

3. From the passage we know that Brock is _________.

A. less than 90 years old

B. over 90 years old

C. a middle-aged woman

4. Which of the following is true?

A. Brock's husband died while she was in China.

B. The villagers got much money from Brock.

C. Brock has made a great contribution to the villages in China.

5. The best title for the passage is _________.

A. A Woman in China

B. A Poor Village in China

C. An American Woman with a Chinese Heart

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C.培养一段时间后,细胞膜上能观察到3H标记

D.若能在高尔基体上观察到3H标记,表示可能有分泌蛋白合成

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A.评标委员会

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体检最可能发现的是

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B.左下肢感觉障碍

C.左下肢缩短、外旋畸形

D.左髋关节屈曲畸形

E.左下肢运动时,腹股沟部出现摩擦音

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A.每月

B.每两月

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D.每半年

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