If the cargo gear on your vessel is equipped with a regular guy and a preventer guy，you should（）.
A. let the schooner guy take most of the strain，thus transferring the load to the opposite boom
B. leave the preventer guy slack
C. secure them as close together as possible on deck
D. secure them so the angle between them is 90°at the boom head
查看答案
独立点火与同时点火相比，省去了（）。
A. 点火器
B. 高压线
C. 火花塞
D. 传感器
为什么有的精馏塔下塔抽污液氮，有的下塔不抽污液氮？
微信支付 
支付宝支付