一般机械中滚动轴承使用最广的是()
A. P6级
B. P0级
C. P2级
规定滚动轴承单一内(外)径的极限偏差主要是为了()
A. 限制变形量过大
B. 方便检测
C. 控制配合性质
规定单一平面平均内(外)径的极限偏差主要是为了()
A. 限制变形量过大
B. 方便检测
C. 控制配合性质
Match each paragraph (A-F) to its main idea:请直接在空格内填大写字母即可,其他什么都不要填,例:D1 Paragraph_______ There are likely to be many more underground cities in Turkey that have not yet been found.2 Paragraph_______ Scientists don't know how old the city is, but it seemed to have enough resources for its people.3 Paragraph_______ A man in Turkey discovered something surprising beneath his house.4 Paragraph_______ The artifacts found in the city below Nevsehir helped scientists work out its age and purpose.5 Paragraph_______ The structure of the hidden city suggests that people used the underground city to hide from danger.6 Paragraph_______ Workers found an underground city in Turkey that was bigger than Derinkuyu.