题目内容：

The Internet plays a big part in human life. We use it for work and entertainment. We can find new recipes on the Interact or advice on staying healthy. We can even use it to learn a new language. We use the Internet to keep in contact with family and friends and stay in touch with issues we care about. The list goes on and on.

Well, there may be no going back to an Internet-free life. But can using the Internet too much be bad for our health? It might be, say researchers. A new study finds that heavy Internet use may be connected to high blood pressure in an unlikely group---teenagers. So, try to be a responsible guardian for your children.

The study results show that teens who spend at least 14 hours a week online are more likely to have high blood pressure. High blood pressure makes your heart and blood vessels work too hard. Over time, this extra strain increases your risk of a heart attack or stroke. High blood pressure can also cause heart, kidney and brain diseases.

The Henry Ford Hospital in Detroit, Michigan did the study. It involved 335 young people, from 14 to 17 years old. One hundred and thirty-four of the teens were described as “heavy Internet users”. Researchers found that out of these 134 teens, 26 had high blood pressure. The researchers say the study is the first one to connect heavy web use with high blood pressure. Another research has connected that heavy Internet use with health problems including anxiety, depression and obesity.

The lead researcher of the study is Andrea Cassidy-Bushrow. For the purpose of the study, she explains, teens considered heavy Internet users were online on average “25 hours a week”. In a statement she said, “Using the Internet is part of our daily but it shouldn’t consume us.”

Ms. Gassidy-Bushrow adds that it is important for teens to take regular breaks from their computers or smart phones and to do some kinds of physical activities. She also suggests that parents limit their children’s use of the Internet to two hours a day, five days a week.

1.The author mainly wants to tell us       .

A. how to prevent high blood pressure.

B. too much Internet use may be bad for teenagers.

C. it’s necessary for teenagers to avoid the Internet.

D. heavy Internet use will worsen teenagers’ memory.

2.What does the underlined sentence in Paragraph 5 mean?

A. People shouldn’t buy goods through the Internet.

B. People shouldn’t waste too much time on the Internet.

C. People shouldn’t fall in love with the Internet.

D. People should control the time length of using the Internet

3.According to Casssidy-Bushrow, teenagers’ use of the Internet should be limited to       .

A. 25 hours a week    B. fourteen hours a week

C. ten hours a week    D. five hours a week

4.The text is mainly intended for       .

A. parents    B. teachers

C. web-designers    D. students