【单选题】Each type of engine has its applications, which on board ship have resulted in the slow-speed main propulsion diesel operating ______cycle.
B.
both on two-stroke and on four-stroke
D.
either on two-stroke or on four-stroke
【单选题】( )后,逐渐形成魏,蜀,吴三国鼎立的局面。
【单选题】Each type of engine has its applications which on board ship have resulted in the slow speed main propulsion diesel operating _____cycle.
D.
either on the two-stroke or on the four-stroke
【单选题】( )检查客房卫生,象征性地称为“白手套”式检查。
【简答题】若目的产物为多组分,收集时可采用()分步收集。