问题 填空题

甲、乙等五名医生被分配到四川灾区A、B、C、D四个不同的岗位服务,每个岗位至少一名医生,则甲、乙两人各自独立承担一个岗位工作的分法共有______种(用数字作答).

答案

由题意知本题是一个分步计数问题,

设5个医生为甲、乙、丙、丁、戊.甲在A、B、C、D四个地方选一个,有4种选择乙在剩下的3个地方选一个,有3种选择丙、丁、戊三人只能选择剩下的两个地方,每人有2个选择,

总共有2×2×2×2=8种,这8种里要去掉3个人都选择同一个地方的情况

即8-2=6∴方法数为4×3×6=72种

故答案为:72

阅读理解

根据每段文字的内容将下列主题词A--E 放到合适的位置作为每段文字的标题.

A .Recover   B.Reuse   C. Repair   D. Recycle   E.Reduce

It's important to learn about protecting our environment. Here is a 5R rule

 for us:

1.____________

If you want to reduce waste, you should use things wisely. Millions of

trees are being cut down to make paper. If people uses paper carelessly

and throws it away, soon we will not have any trees left. Other tings are

also being wasted, and people don't know what to do with waste in big

cities. So it is necessary to reduce waste.

2. ______________

You should always think of reusing usable things before throwing them

 out. Give the clothes you do not use or the ones which are too small to

the poor. Within a family, you can pass on such clothes to younger

brothers or sisters.

3. _______________

Bottle, cans and paper can easily be recycled. By doing this we save

lots of time and money. For example, coke cans can be sent to a factory,

where they are smashed flat and melted and the metal can be made for

new coke cans.

4. ____________

When you buy a box of apples, there may be a few rotten apples. So you

have two choices: one is to throw those apples away, or another is to cut

off the rotten parts and use the good parts. In this way, you recover the

eatable parts of the fruit.

5. ______________

If one of the legs of your table is broken, you should repair it instead

of throwing it away. However, if you want to change your furniture, it

is better to sell old things or give them to other people who can use

them after doing some repairs. It is true that North America is a

"throw-away" society, but the time has come to change our way

of life so that we can protect our environment. Every one of us

should try our best.

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