检验输精管经皮穿刺是否成功的方法有哪些

A．精囊灌注试验

B．输精管盲腔加压注气试验

C．针头进入输精管前壁时的感觉

D．刺入的六号针头皮下不能扪及，拨动针头时输精管和针头移动方向一致

E．向管内精囊端灌注1％普鲁卡因，受术者有尿意而针头周围无皮下水肿

Which statement is TRUE concerning gasoline vapors on board a vessel（）.

A.They are heavier than air and will settle in the lowest part of the vessel

B.They are lighter than air and will settle in the highest part of the vessel

C.They should be vented into the engine to improve combustion

D.They should be vented into the wheelhouse