问题 选择题

下列各组数据表示三条线段的长。以各组线段为边,不能构成三角形的是

A.5,12,13

B.7,24,25

C.1,2,3

D.6,6,6

答案

答案:C

题目分析:三角形的基本关系满足,两边之和大于第三边,两边之差小于第三边,本题中唯一不能构成三角形的是C,不满足三角形的三边的基本关系,故选C

点评:本题属于对三角形的三边的基本关系的理解和运用

阅读理解

阅读理解。

    Do you always understand the directions (说明) on a bottle of medicine? Do you know what it meant by

"Take only as directed?" Read the following directions and see if you understand them.

    "To reduce pain, take two tables (药片) with water, followed by one tablet every eight hours, as required.

For night-time and early morning relief (缓解疼痛) take two tablets at bedtime. Do not take more than six

tablets in twenty-four hours." For children six to twelve years old, give half the amount (量).

    For children under six years old, ask your doctor's advice.

    Reduce the amount if you suffer from restlessness or sleeplessness after taking the medicine.

1. How many tablets at most can a person over 12 have in 24 hours?

A. Three

B. Four

C. Six

D. Eight

2. How many tablets should a nine-year-old child normally take in 24 hours?

A. Half a tablet.

B. One tablet.

C. Two tablets.

D. Four tablets.

3. What is the advice for one who can not sleep well after taking the medicine?

A. Stop taking the medicine at bedtime.

B. Continue to take the normal amount.

C. Take more than the normal amount.

D. Take less than the normal amount.

4. It can be inferred from the directions that this medicine ________.

A. helps you to fall asleep quickly

B. may be dangerous to small children

C. can not be taken if one feels sleepy

D. should not be taken by children under six

5. This text is most probably taken from a ________.

A. textbook

B. newsreel (记录片)

C. doctor's notebook

D. bottle of medicine

问答题