问题 问答题 简答题

简述生球落下强度测定方法。

答案

参考答案:(1)取13--18mm生球10个,

(2)落下高度500mm,

(3)自由落在10mm厚的钢板上,

(4)规定完全破裂成块的落下次数,

(5)取算术平均值为一次测定结果。

阅读理解

阅读理解。

     The ostrich (鸵鸟) is the largest bird in the world. From far away , it looks more like a camel than a

bird. It has a long neck, long legs and a walk like a camel. Its eyes are very large and sharp . Like the

camel ,  the ostrich can go for a long time without water . It lives in sandy desert , too .

Its wings are too short for flying , but they do help the ostrich to run fast. The wind gets under the wings

and lifts the bird off the ground . In this way , it can take very long steps. An ostrich can run faster than a

horse .

     Ostriches are  big and strong , but sometimes they do not seem very smart.

     When they are afraid, they run around in circles.

     Ostrich eggs are large . The shells are very strong . They are so strong that they can be used for cups

and bowls.

1.The ostrich ________

A. is larger than a camel

B. is as large as a camel

C. is larger than any other bird

D. looks like each other

2. The ostrich and camel both have ________

A. sharp eyes            

B. long legs

C. short wings            

D. to go without water

3. The ostrich ________

A. can fly fast with the help of its wings 

B. can run fast with the wind

C. can’t fly because it has such short wings 

D. can run fast with the help of its wings

4. What can lift the ostrich off the ground?

A. its wings    

B. its legs    

C. The wind    

D. its long neck

5. People can use ________ for cups and bowls.

A. the shells of ostrich eggs        

B. ostrich eggs 

C. ostrich itself                  

D. ostrich wings

单项选择题