要使5□2÷56的商是两位数,□里最小可填______;要使它的商是一位数,□里

题型:填空题

问题:

要使5□2÷56的商是两位数,□里最小可填______;要使它的商是一位数,□里最大可填______.

考点:认识除法
题型:填空题

一列横波沿x轴传播,在t=0时刻的波形如图中实线所示,在t=1s时刻的波形如图中虚线所示.求:

①这列波的波长;

②这列波的波速.

题型:填空题

随着社会主义经济的发展,人们对非物质利益的追求,即精神上的追求会越来越占有重要的位置。要调动人们提高经济效率的积极性和主动性,除了利用物质利益原则来调节外,更好地满足人们的精神需要是必不可少的。因此 ( )

A.当人们的货币收入达到一定水平时,非物质利益的激励作用会逐渐增大,而物质利益对经济效率的推动作用则会呈递减状态

B.精神上的追求必须建立在物质利益的基础上,精神上的追求是次要的,而物质利益的追求更主要

C.当人们的货币收入达到一定水平时,物质利益的激励作用就不存在了,非物质利益的激励作用成为惟一的作用

D.非物质利益与物质利益是相互矛盾的,不能把它们放在一起比较

题型:填空题
一堆煤12吨,用去
()
()
,还剩4吨;用去______吨,还剩
1
3
题型:填空题

B


Each year there is an increasing number of cars on roads and street are millions of new cars are produced. One out of every six Americans works at putting together the parts of cars, driving trucks, building roads of filling cars with gas. Americans won’t live without cars!
Most Americans find it hard to think what life would be without a car. However some have realized the serious problem of air pollution by cars. The polluted air is poisonous(有毒的) and dangerous to health.
One way to get rid of(排除)the polluted air is to build a new kind of car. That’s what several of the large car factories are trying to do. But to build a clean car is easier said than done. Progress in this field has been slow.
Another way is to take the place of the car engine(发动机) by something else. Engineers are now working on some new cars. Many makers believe that it will take years to develop a practical model that pleases man.
To prevent the world from being polluted by cars, we’ll have to make some change in the way many of us live. Americans, for example, have to cut down on the number of their cars. They are encouraged to travel and go to work by bike. Riding a bike is thought to help keep the air clean.
But this change does not come easily — a large number of workers may find themselves without jobs if a car factory closed down. And the problem of air pollution would become less important than that of unemployment(失业).
Although cars have brought us a better life, they have also brought us new problems.

Which fact does the passage provide ( )

A.About one sixth of American workers are working in car factories.

B.The best way to get rid of air pollution is to change the car engine by something else.

C.It isn’t easy to change the way of life in the USA.

D.In the USA bikes will surely take the place of cars in the future.

题型:填空题

尘笼吸气负压的调节原则是什么?

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