题目内容

为保证混凝土的耐久性,配合比设计中不但要严格控制水灰比,还应控制()。

A. 用水量
B. 骨料级配
C. 砂率
D. 水泥用量

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混凝土中水泥的选用原则是()。

A. 高强高配
B. 高强低配
C. 低强高配
D. 随便配

坍落度试验时,混凝土拌合物分层装入标准圆锥筒内,每层用弹头棒均匀的捣插()次。

A. 20
B. 25
C. 30
D. 35

我国现行规范(GBJ10--1999)规定,普通混凝土按立方抗压强度标准值划分为()个等级

A. 6
B. 10
C. 14
D. 20

How did the early people do their counting? At first, they did all their counting with smallstones. Later, they learned to use their fingers in counting. Since man has ten fingers the number10 became the1 of all counting in many parts of the world.In 1946 the first electronic computers went into2. Since its invention the computer has changed greatly, and it has more and more uses. It can3 people from difficult measurement and computation.There are4 computations in science and engineering. Scientists are unable to make them, but the computer can do them quickly and5 . For instance, a spaceship cannot leave the earth and go to the moon without computers. What must the spaceship be like? When can it leave? Will it be onthe right6 ? The computer must answer all these questions.In recent years more and more people have used computers not only in production and technology,butalso in everyday life, for the simple reason that they are far more 7 than man. They have much better memories and can8 large amounts of information. No man9can do 500,000 sums in one second, but a computer can.In fact, computers can do many of the things we do, but faster and better. They can10 machines in factories, work out tomorrow’s weather,and even do translation work.In the future we are going to use computers for almost everything almost every day.

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