锯削时,为了提高效率,锯条往返均需施加压力,因为回锯时也产生一定的切削量。
参考答案:错
A. go down B. catch more fish C. heavy D. hungry E. happy F. richest
G. the boat and life H. sell the gold chains(链条) I. fishing J. poor
Mr Smith lived by the sea. He had a big family and he had to work hard, or his wife and children would be __小题1:__. So he had to get up early every day. After breakfast he set out in a small boat. He always hoped to __小题2:__.
One morning the man got to a good place for fishing. He threw a long rope with many hooks(钩子)into the water. He found it very ___小题3:___ and pulled the hooks out of the sea. He saw there were some gold chains(链子. He , of course, was very __小题4:__.
“I’ll __小题5:__ for a lot of money ,” he thought to himself.“I’ll build a new house and buy expensive things. I’ll be the __小题6:__ man in the world!”
Mr. Smith went on drawing his rope and didn’t notice what was happening to his boat. It began to __小题7:__. As he was pulling the gold chains, the boat sank into the sea. He lost not only the gold chains ,but also __小题8:___!
在站场工艺中截止阀常用于()管线上。
A.排污
B.放空
C.旁通
D.进站