瓦斯积聚的标准是体积大于()立方米的空间内、瓦斯浓度达到2%为瓦斯积聚。
A、0.5
B、1.0
C、1.5
参考答案:A
用所给词的适当形式填空。
1. He jumped on the horse and ________ (ride) away.
2. The uncle caught three ________ (fish) yesterday.
3. My aunt is good at ________ (fry) fish and I like to eat ________ (fry) fish very much.
4. She likes taking ________ (walk) after dinner.
5. There are many kinds of________ (fish) in the river.
6. Sweden (瑞典) is in ________ (Europe). It is________ _________ (Europe) country.
7. He comes from ________ (Greece). He speaks ________ (Greece). The ________ (Greece)
are friendly.
8. He ________ (leave) for Beijing yesterday.
9. I want ________ (take) a long vacation this summer.
10. My uncle is a good fisherman. I would like ________ (go) fishing with him.
图示为三种形式的吊车的示意图,OA为杆,重力不计,AB为缆绳,当它们吊起相同重物时,杆OA受力的关系是( )
A.a>b>c
B.a>c=b
C.a=b>c
D.a=b=c