Question

Scientists in Colombia have trained a team of rats to help remove land mines from the countryside. Land mines are small bombs hidden in the ground and designed to explode(爆炸) when someone steps on them. When trained, the rats can smell special metals in the mines and then signal(发信号) to their human team. Then why use rats for such an important job?

In the past, dogs have been used to find bombs. Rats have a good sense of smell and can respond to orders, just like dogs do. But rats are much lighter than dogs. They stand less of a chance of setting off the mines, which explode under a certain amount of weight. What’s more, the best rats are cheaper to keep than dogs. It costs about the same amount of money to take care of one dog as it does 70 rats.

The rats have already been used in Tanzania, an African country with many land mines. Luisa Fernanda Méndez and her team in Colombia are training the even lighter Wistar rats. These are the white rats with red eyes that scientists often use in laboratory experiments. “They even train their babies to perform their jobs, which saves us a lot of time, ” Méndez said.

Colombia has the second-highest rate(比率) of deaths from land mine accidents in the world. Last year, land mines killed 695 people — 56 of whom were children. A criminal group called the Revolutionary Armed Forces of Colombia, or FARC, as well as other organizations, have placed the mines. FARC are strongly against Colombia’s government. The group has placed mines all around its own bases and in many places in the countryside.

In the past, the Colombian government hired peasants and poor farmers to find mines. Many of them died trying to find the well-hidden bombs.

Colombian police official Erick Guzmán hopes the team of rats can come to the rescue(援救). “These rats will be a great help,” he said.

1.How do rats help to find land mines?

A.By their special sight. B.By their light weight.

C.By their sense of smell. D.By their excellent hearing.

2.The advantage of rats over dogs in finding bombs is that _____.

A.they are cleverer.

B.they run faster.

C.they have a better sense of smell.

D.they don’t make mines explode as easily.

3.The underlined word “They” may refer to ______.

A.scientists. B.Wistar rats.

C.dogs. D.Méndez and her team.

4.What is the passage mainly about?

A.Specially-trained rats help clear land mines.

B.People in Tanzania are suffering from land mines.

C.Dogs are no longer used to find land mines.

D.Land mines have become a great danger to Colombians.

Answer

1.C

2.D

3.B

4.A

【解析】

这是一篇说明文。本文介绍了科学家们在哥伦比亚已经训练一组老鼠帮助在农村清除地雷。以前用狗来帮助清除地雷，老鼠的优势他有灵敏的嗅觉，能够闻出特殊的金属味，并且他们的体重轻引爆地雷的可能性小，还有养它们的费用比养狗的费用低。

1.细节理解题。根据the rats can smell special metals in the mines and then signal(发信号) to their human team.可知，老老鼠能闻到矿井里的特殊金属，然后向人类发出信号。所以老鼠通过嗅觉帮助发现地雷。故选C。

2.细节理解题。根据第二段But rats are much lighter than dogs. They stand less of a chance of setting off the mines,但是老鼠比狗更轻。他们的体重轻引爆地雷的可能性小。所以在寻找炸弹方面，老鼠比狗的优势在于他们不会让地雷那么容易爆炸。故选D。

3.词义猜测题。根据第三段Luisa Fernanda Méndez and her team in Colombia are training the even lighter Wistar rats. These are the white rats with red eyes that scientists often use in laboratory experiments可知，路易莎·费尔南达·门德斯和她在哥伦比亚的团队正在训练更轻的Wistar老鼠。这些是科学家在实验室实验中经常使用的红眼白鼠。所以通过上下文的语境可以判断出，they指的是上文提到的是Wistar老鼠。故选B。

4.主旨大意题。通读全文尤其是第一段“Scientists in Colombia have trained a team of rats to help remove land mines from the countryside”可知，本文介绍了科学家们在哥伦比亚已经训练一组老鼠帮助在农村清除地雷，所以短文主要是关于经过特殊训练的老鼠帮助清除地雷。故选A。