问题 单项选择题

在规定的试验条件下,液体挥发的蒸气与空气形成的混合物,遇火源能够闪燃的液体最低温度,称为()。

A.燃点

B.闪点

C.自燃点

D.爆炸点

答案

参考答案:B

解析:在规定的试验条件下,液体挥发的蒸气与空气形成的混合物,遇火源能够闪燃的液体最低温度,称为闪点。在规定的试验条件下,应用外部热源使物质表面起火并持续燃烧一定时间所需的最低温度,称为燃点。在规定的条件下,可燃物质产生自燃的最低温度,称为自燃点。在这一温度时,物质与空气(氧)接触,不需要明火的作用,就能发生燃烧。

阅读理解

Scientists find that hardworking people live longer than average men and women.Career (职业)women are healthier than housewives.Evidence shows that the jobless are in poorer health than the jobholders.An investigation shows that whenever the unemployment rate increases by 1%,the death rate increases by 2%.All this comes down to one point.work is helpful to health.

Why is work good for health? It is because work keeps people busy away from loneliness.Researches show that people feel unhappy, worried and lonely when they have nothing to do.Instead the happiest are those who are busy.Many high achievers who love their careers feel that they are happiest when they are working hard.Work serves as a bridge between man and reality. By work people come into contact with each other.By collective(集体的)activity they find friendship and warmth.This is helpful to health.The loss of work means the loss of everything.It affects man spiritually and makes him ill.

Besides,work gives one a sense of achievement.Work makes one feel his value in society.When a writer finishes his writing or a doctor successfully operates on a patient or a teacher sees his students grow, they are happy beyond words.

From the above we can come to the conclusion that the more you work the happier and healthier you will be.Let us work hard and study hard and live a happy and healthy life.

1.What may be the reason why housewives are not as healthy as career women?

A.Housewives are poorer than career women.

B.Housewives have more children than career women.

C.Housewives have less chance to communicate with others.

D.Housewives eat less food than career women.

2.Which of the following statements is TRUE according to Paragraph 2 ?

A.Busy people have nothing to do at home.

B.High achievers don’t care about their families.

C.There is no friendship and warmth at home.

D.A satisfying job helps to keep you healthy.

3.The best title for this passage may be “               ”

A.People Should Find a Job

B.Working Hard Is Good for Happiness and Health

C.People Should Make More Friends by Work

D.The Loss of Work Means the Loss of Life

填空题