在液压缸密封中,()密封圈应用最为广泛。
A.0形
B.Y形
C.V形
D.唇形
参考答案:A
I failed again in the examination and only then _____ how much time I had wasted.
A.I realized
B.I had realized
C.did I realize
D.had I realized
人身保险与社会保险的区别表现不包括()。
A.保障对象不同
B.经营主体不同
C.行为依据不同
D.实施方式不同