若正实数a,b满足a+b=1,则( ) A.1a+1b有最大值4 B.ab有最小值1

题型:选择题

问题:

若正实数a,b满足a+b=1,则(  )
A.
1
a
+
1
b
有最大值4
B.ab有最小值
1
4
C.
a
+
b
有最大值
2
D.a2+b2有最小值
2
2
考点:基本不等式及其应用
题型:选择题

阅读理解

       John Brown, an office worker, lives in Washington, and he inherited(继承)$1,000,000 when he

was 23. He didn't feel happy at all. His college friends were looking for their first jobs, but he didn't

have to. John decided to keep living a simple life like everyone else. He didn't tell any of his friends

and gave$100,000 of his money to a charity(慈善团体) that helped poor children to live better

lives. Today he is 36. He still wears cheap shoes and clothes and owns a small car only, but he is

much happier.

       Up to now John has helped 15 children from poor countries all over the world, $200 a month

for each. The child does not receive the money in cash(现金). The money pays for the child's school

expenses, food, medical care and clothing. John receives a report each year on the child's progress.

They can write to each other, but usually the children do not speak English. 

       When John first heard about these children, he wanted to help them."It was not

anything special,"he said, "Until I had the chance to go to these countries and meet the children I was

helping, I did not know any thing about the type of life they had."

       Once John went to meet a little girl in Africa. He said that the meeting was very

exciting.

       "When I met her, I felt very very happy," he said," I saw that the money was used

for a very good plan. It brought me closer to the child in a way that giving money alone cannot." "I

want to do everything I can. I will go on helping those children in need." he added.

根据短文内容回答下列问题

1. What kind of life is John living?

He is living a _____________________________________________________

2. Did John want to look for a job or stay at home after he got the money?

_______________________________________________________________

3. Does John only help the poor children in Africa?

_______________________________________________________________

4. The child receives the money in cash, doesn't he?

_______________________________________________________________

5. Why did John say that the meeting with the little girl was very exciting?

Because he saw his money was well used and this made him_____________.

6. How do you like John Brown?

He is___________________________________________________________

题型:选择题

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B.大血藤

C.莪术

D.麦冬

E.鸡血藤

题型:选择题

下列人体细胞中,不含有细胞核的是( )

A.组织细胞

B.成熟的红细胞

C.白细胞

D.神经元

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A.6个

B.8个

C.10个

D.12个

E.16个

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A.吴楚七国之乱

B.靖难之役

C.八王之乱

D.异姓王反叛

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