机械密封的主要作用是将泄漏的轴向密封改为难泄漏的()。
A.径向密封
B.填料密封
C.密封函
D.环向密封
参考答案:A
40 kilometers _____ Chengdu lies a town, _____ suffered great losses in the earthquake, but is now on the road to recovering.
A.west of; which
B.on the west in; where
C.west of; where
D.on the west of; which
金融债券的期限主要是()的。
A.长期
B.中期
C.短期
D.不确定