立磨主减速机推力瓦采用的是（）润滑，管磨的中控轴承是（）润滑。
参考答案：静压；动压
Over two hundred years ________ since the United States ________in 1776[ ]
A. have passed; founded
B. has passed; were founded
C. have passed; was founded
D. has passed; was founded
在Word中，选定一行文本的技巧方法是（）。
A.将鼠标箭头置于目标处，单击
B.将鼠标箭头置于此行的选定栏并出现选定光标单击
C.用鼠标在此行的选定栏双击
D.用鼠标三击此行
