阀杆缺乏润滑或润滑剂失效，将造成（）。
A.阀杆升降不灵活
B.关闭件泄露
C.填料室泄露
D.垫圈泄露
参考答案：A
Gradually, you will realize that the things that matter are that can't be bought with money. [ ]
A. these
B. ones
C. those
D. some
外感风寒挟湿之头痛，身痛等表寒重证，首选
A.麻黄
B.紫苏
C.羌活
D.白芷
