问题
单项选择题
关于压缩机喘振的原因,下列表述正确的是()。
A.气体分子量减小
B.吸入温度降低
C.吸入压力升高
D.气体分子量增大
答案
参考答案:A
关于压缩机喘振的原因,下列表述正确的是()。
A.气体分子量减小
B.吸入温度降低
C.吸入压力升高
D.气体分子量增大
参考答案:A
完形填空。 | ||||
Here is a story about a clever dog. It was a seeing-eye dog. A seeing-eye dog can help blind (瞎的) people walk along the streets and do many other things. One day a seeing-eye dog and a blind man 1 on bus together. The bus was full of 2 and there were 3 seats left. But one man soon stood up and left his seat. The dog 4 the blind man to the seat, but there was little space (空间) for two people. The dog began to push the people on each side 5 his nose. He pushed and pushed until the people moved and 6 there was 7 space for two people. The blind man then sat down and the dog got up on the seat at his side. The dog 8 down and put his head on the leg of the 9 man. He was very comfortable and soon fell asleep. Everyone on the bus 10 at the dog. | ||||
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