考考你的推理能力

请阅读下面的短文，然后做后面的题目。

Four friends live in a small town. Their names are John, Miller, Smith and Carte. They all have different jobs. One is a policeman, one is a cook, one is a farmer, and one is a doctor.

It’s Tuesday afternoon. John’s son breaks his leg and John takes him to the doctor. The doctor’s sister is Smith’s wife. The farmer isn’t married. He has a lot of hens.

Miller often buys eggs from the farmer. The policeman sees Smith and Miller every day for they are neighbours.

Now who is the policeman? Who is the cook? Who is the farmer? Who is the doctor?

1. John is a _______.

A. doctor       B. farmer       C. policeman D. cook

2. Miller is a _______.

A. doctor       B. policeman C. cook         D. farmer

3. Smith is a _______.

A. farmer       B. policeman C. cook         D. doctor

4. Carter is a _______.

A. doctor       B. policeman C. cook         D. farmer

【答案与解析】这是一篇推理性文章，要求根据所给出提示，猜出各自的职业。

以上4题答案分别为C、A、C、D。有一定难度，且需要一定的推理，现分析如下：

1. 因为John 的儿子腿摔断了要去看医生，故可推知John不是doctor。

2. 因为医生的妹妹是Smith的妻子，故Smith不是doctor(否则兄妹结婚，不合情理)。

3. 由于 farmer 没有结婚，所以 Smith 和 John 都不是farmer (因为Smith 有妻子，John 有儿子)。

4. 因为警察每天看到Smith，所以 Smith不是policeman。(from www.nmet168.com)

5. 由以上分析可知，Smith 不是 doctor，也不是 farmer，也不是 policeman，所以只能是 cook。

6. 由于 Miller常从farmer 处买鸡蛋，所以 Miller 不是 farmer。

7. 由以上分析可知，John, Miller 和 Smith 都不是 farmer，所以 Carter 一定是farmer。

8. 由于警察每天除看到 Smith 外，还看到 Miller，所以 Miller 不是警察。既然他不是警察，而且前面已分析出 Smith 是 cook，Carter 是 farmer，所以 Miller 一定是 doctor。

9. 最后剩下的 John 便是policeman。

同学们在做题时可以一边推理，一边填写下表：

	policeman	cook	Farmer	doctor
John	√		×	×
Miller			×	√
Smith	×	√	×	×
Carter			√