问题
单项选择题
装有动密封环的离心泵,其轴向推理大小与()直接相关
A、叶轮吸口内径
B、叶轮吸口外径
C、密封环内径
D、密封环外径
答案
参考答案:D
装有动密封环的离心泵,其轴向推理大小与()直接相关
A、叶轮吸口内径
B、叶轮吸口外径
C、密封环内径
D、密封环外径
参考答案:D
Have you ever seen the man in the moon? If you look closely at the moon on some nights, you can see the face of the man in the moon. Some people say that they can see an old man carrying sticks.小题1: These pictures are made by the mountains and plains of the moon. Long ago people in England used to tell their children that the moon was made of green cheese.小题2: The moon is a large round rock. It is completely bare. There are no trees or plants on the moon. There are no rivers or seas. There are no living things. It never rains on the moon, and everything is covered with dirty, white dust. 小题3: When the sun shines on it, the moon is very hot, in the shade, however, it is as cold as ice.小题4: It does not weigh as much as the earth. If you went to the moon, you would weigh six times less than you do now. 小题5: 仔细阅读短文,将下面五句话还原到文中空白处,并将其标号填入答题栏的相应位置。
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