问题 选择题

将695600保留两个有效数字的近似数是(    ).

A.690000

B.700000

C.6.9×l05

D.7.0×l05

答案

答案:D

一个近似数的有效数字:从左边第一个不是0的数字起,后面所有的数字都是这个数的有效数字.

精确到十位或十位以前的数位时,要先用科学记数法表示出这个数,再进行四舍五入.

解:695600保留两个有效数字的近似数是7.0×105

故选D.

阅读理解

阅读理解。

     If you're a male and you're reading this, congratulations! You're a survivor. According to statistics, you're

more than twice as likely to die of skin cancer as a woman, and nine times more likely to die of AIDS.

Assuming you make it to the end of your natural term, about 78 years for men in Australia, you'll die on average

five years before a woman.

     There're many reasons for this-typically, men take more risks than women and are more likely to drink and

smoke but perhaps more importantly, men don't go to the doctor.

     "Men aren't seeing doctors as often as they should," says Dr. Gullotta. "This is particularly so for the over-

40s, when diseases tend to strike. According to a recent survey, 95% of women aged between 15 and early

40s see a doctor once a year, compared to 70% of men in the same age group.

     "A lot of men think they're unbeatable," Gullotta says. "They only come in when a friend drops dead on the

golf course and they think, Geez, if it could happen to him …"

     Then there's the ostrich (鸵鸟) approach. "Some men are scared of what might be there and would rather

not know," says Dr. Ross Cartmill.

     "Most men get their cars serviced more regularly than they service their bodies," Cartmill says. He believes

most diseases that commonly affect men could be addressed by preventive check-ups. 

      "Prevention is cheaper in the long run than having to treat the diseases. Besides, the final cost is far greater,

it's called premature death."

1. Why does the author congratulate male readers at the beginning of the passage?

A. They have lived long enough to read this article.

B. They are sure to enjoy a longer and happier life.

C. They can live longer than they expected.

D. They are more likely to survive serious diseases now.

2. Why does the author congratulate male readers at the beginning of the passage?

A. They have lived long enough to read this article.

B. They are sure to enjoy a longer and happier life.

C. They can live longer than they expected.

D. They are more likely to survive serious diseases now.

3. Which of the following best completes the underlined sentence "Geez, if it could happen to him..."

    (in Para 4)?

A. I should consider myself lucky.

B. it would be a big misfortune.

C. I should avoid playing golf.

D. it could happen to me, too.

4. What does Dr. Ross Cartmill mean by the ostrich approach (in Para 5)?

A. A casual attitude towards one s health conditions.

B. Unwillingness to find out about one's disease because of fear.

C. Refusal to get medical treatment for fear of the pain involved.

D. A new treatment for certain psychological problems.

单项选择题