问题 选择题

汽车里面包含了许多物理知识,下列说法正确的是(  )

A.汽油机做功冲程将机械能转化为内能

B.正确使用安全带是为了防止惯性带来的危害

C.用水作为汽车发动机的冷却剂,其重要的原因之一是水的比热容较小

D.零陵大道限制最高车速80km/h,合8m/s

答案

A、汽油机的做功冲程将内能转化成机械能,该选项说法不正确;

B、正确使用安全带是为了减小汽车紧急刹车时惯性带来的危害,该选项说法正确;

C、因为水的比热容较大,相同质量的水和其它物质比较,升高相同的温度,水吸收的热量多,所以汽车发动机用水做冷却剂,该选项说法不正确;

D、零陵大道限制最高车速80km/h,80km/h=80×

1
3.6
m/s≈22.2m/s,该选项说法不正确.

故选B.

阅读理解

阅读理解。

     Have you ever heard of the story of Earth Day? Now let me tell you.

     Earth Day was started 111 1970 by a man named John McConnell from the United States. In the

beginning,  it was held on one day in spring when the day and night are of the same length around the

world.Now it is celebrated on April 22nd.  Earth Day is now celebrated all over the world.

     Earth Day is a very special, day.'It makes all of us think about problems we make for the earth. It

is not only a special day in the city where we live, but a day that the whole world celebrai.e.

     Some countries-have Earth Day celebrations, and some people and groups join in Earth Day projects(计划) such as "Protect Our Home" and "Water for life".

     You can join in one of the projects, or start one of your own. It can be something small like planting

a tree with your mom,  or something large like cleaning up a park with your classmates or frierjds.  You

can do almost anything. Try to think of something you would like to do.

     Why do we celebrate Earth Day? Because we have only one earth and it is our only home. It is

getting very dirty.  It is our ducy to protect our beautiful home. Earth Day is a day to call on people

around the world to save our earth.

1.  An_______called John McConnell started Earth Day in 1970 and now it is celebrated all over the

world on the_______of April.

2.  On Earth Day people don't_______celebrate this special day but also think more about what's to the

earth.

3. Some countries have different Earth Day _______by _______in Earth Day projects.

4. It doesn't matter whether your project is_______.

5. We celebrate Earth Day to _______people around the world to_______our earth.

单项选择题