阀门的梯形螺纹、阀杆螺母与支架滑动部位、轴承部位,齿轮和蜗轮、蜗杆的啮合部位,以及其他配合()部位,都需要良好的润滑。
A、固定
B、表面
C、接触
D、活动
参考答案:D
_______ good use of learning resources such as the website and library, and you will make great progress.
A.To make
B.Making
C.Make
D.Having made
章秋柳