A recent study offers a picture of how dangerous it is to get a lift from a teenage driver. Indeed, a 16-year-old driver with three or more passengers is three times as likely to have a fatal（致命的）accident as a teenager driving alone. However, the possibility of death for drivers between 30 and 59 decreases with each additional (added) passenger.

　　It was also found that the death rates for teenage drivers increased greatly after 10 p.m., and especially after midnight. With passengers in the car, the driver was even more likely to die in a late night accident.

　　Robert Foss, a scientist at the University of North Carolina Highway Safety Research Center, says the higher death rates for teenage drivers have less to do with “really stupid behavior” than with just a lack of driving experience. Both he and the author of the study believe that the way to help solve the problem is to have states setting up so-called graduated licensing systems（等级执照制）. A graduated license requires that a teenager first prove that he/she is able to drive in the presence of an adult, followed by a period of driving with a limited number of passengers, before graduating to full driving on his own. About half of the states now have some sort of graduated licensing system in place. The systems have reduced teenage driver crashes（相撞）, according to recent studies.

1.Which of the following situations is most dangerous according to the passage?

A．Adults giving a lift to teenagers on the highway after 10 p.m.

B．A teenager driving after midnight with passengers in the car.

C．Adults driving with three or more teenage passengers late at night.

D．A teenager getting a lift from a stranger on the highway at midnight.

2.According to Robert Foss, the high death rate of teenage drivers is mainly because __.

A．their preference for driving at night

B．their lack of driving experience

C．their careless way of driving

D．their driving with passengers

 

1 

Three kids have been learning chemistry for only a few months. But they have already begun to challenge (挑战) a world famous scientist!

Li Weichi, Huang Runling, and Xiao Yan are from Zhongshan Huaqiao Middle School in Guangdong. They have just found a red cabbage that could be a new kind of acid-base indicator (酸碱指示剂). They want it to take the place of litmus (石蕊) paper.

"We've learnt to think of and ask questions about life by ourselves," said Li, "We work well with each other."

British scientist Robert Boyle discovered the use of litmus paper over 300 years ago. Now it is used widely in experiments all over the world.

But when the kids did some experiments in class last winter, they saw that the litmus paper didn’t turn very blue with base matter. It's hard to get a clear result.

Will there be a better indicator than litmus paper? The three kids decided to try and find out!

How? They went to collect over 40 plants in parks, gardens and markets. Then they ground (研磨) leaves, flowers and stems (茎) to get the pigments (色素) from them.

The kids mixed pigments with acid and base. They spent months watching carefully to see which paper showed the best color change. They decided it was the litmus paper!

"It's our first scientific journey, Huang said, "But it makes me want to try harder."

1.Whom did the three kids want to challenge?

A. Their chemistry teacher.

B. Their headmaster.

C. Robert Boyle

D. Thomas Edison

2.From the text, a red cabbage is a kind of ____.

A. plant　　B. animal　　C. paper　　D. liquid

3.What is widely used as the acid-base indicator now?

A. red cabbage              B. litmus paper

C. any plant                D. any flower 

4.The story mainly tells us ____.

A. how to make litmus paper

B. about the three kids' spirit

C. scientists were wrong

D. the kids are heroes