Except in rare cases,it is impossible to extinguish a shipboard fire by（）. ["removing the heal","removing the oxygen","removing the fuel","interrupting the chain reactio"]
新生儿和小婴儿有哪些表现应该考虑严重心血管畸形的可能？
叙述低压精馏塔和闪蒸槽系统工艺流程。
下列各项，不属于放样的基本元素是（）。 ["水平角","竖直角","水平距离","高差"]
叙述蒸馏塔系统工艺流程。
企业有哪些折扣和折让定价策略？
