【简答题】滚动轴承的核心元件是(),它使相对运动表面间的滑动摩擦变为滚动摩擦。
【单选题】What is the main idea of Para 5-7(last three paragraphs)?
A.
DNA's future tendencies.
【单选题】(Para 7)It's been six years since he _____ from college.
【简答题】滚动轴承的核心元件是滚动体,它使相对运动表面间的滑动摩擦变为()。
【单选题】According to 'the Queen's Golden Jubilee' (Para.3), how long has been the reign of the Queen?
A.
It has to be 25 years under the reign of the Queen.
B.
45 years should be the minimum for the Queen's Golden Jubilee.
C.
At her age of 50, people usually celebrate the Queen's Golden Jubilee.
D.
The Queen's Golden Jubilee would be celebrated at her 50 year's reign.