The oil discharge monitoring system in the

导致肥厚型心肌病最常见的原因是（）

A.遗传

B.中毒

C.代谢异常

D.药物作用

E.病毒性心肌炎

( ) can be issued by the entry - exit inspection and quarantine authorities of the P.R. of China.

A．B/L

B．Certificate of Origin

C．L/C

D．Packing List

Look out, David! A car is coming. [ ]

A. Don't run

B. Walk fast

C. Be careful

D. Take care of

引起疱疹性咽喉炎的病原体为：（）

A.鼻病毒

B.流感病毒

C.副流感病毒

D.腺病毒

E.柯萨奇病毒

气动气缸的主要密封构件有哪些？