问题
单项选择题
凸轮轴的主要作用是根据工作过程的需要使气门（）。
A.常闭
B.常开
C.开启和关闭
答案
参考答案：C
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凸轮轴的主要作用是根据工作过程的需要使气门（）。
A.常闭
B.常开
C.开启和关闭
参考答案：C
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| It was just getting dark. There was a touch of fog and I was on a lonely stretch of road. 1 I was going along cheerfully, thinking about the dinner I would eat when I got to Salisbury. I was going along 2 at about thirty-five miles an hour when suddenly I heard a scream, a 3 scream- " Help!" I looked round, but the only 4 of life was a large, black, rather suspicious-looking (可疑的) car just 5 a bend in the road about a hundred yards away. That was where the cry had come from. I 6 speed and went after it. I think the driver saw what I was doing, for he did the same and began to draw 7 me. As I drew near, the girl's voice came again, a lovely voice but trembling with 8 . "Let me go, you coward; you're hurting me. Oh! Oh!" I felt my 9 boil. The fog was coming down 10 now, and the countryside was lonelier. I had no 11 that the murderous guy in the car noticed this. Again came a cry. "Drop that knife, you fool. Oh!" Then a cry and a groan (呻吟). If I was to save her, it was now or 12 . Perhaps even now I was too late. But if I couldn't save the girl, I would at least try to bring the murderer to 13 . The car was only a couple of yards away now. I drove the bike right across its 14 , and its brakes (煞车) screamed as the driver tried to pull it over and 15 into the ditch (沟) at the side of the road. The door of the car was pushed open angrily and a dark, evil-looking fellow stepped out. "You fool!" he shouted as he came towards me with his fist raised to hit me. But I was 16 than he. I put all I could into 17 that would have knocked out Joe Louis. It 18 him right on the point of the chin; his 19 slowly bent under him, and he dropped to the ground without a sound. I rushed to the car, 20 open the door and looked inside. There was no girl there. Suddenly from the back of the car came a voice. "You have been listening to a radio play, Murder in Hollywood, with Mae Garbo and Clark Taylor. The news will follow immediately." | ||||
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