Gas turbines differ from steam turbines in that （）. ["steam rather than gas is used to turn a shaft","vapor rather than gas is used to turn a shaft","the former uses gas to turn a shaft","the latter uses gas to turn a shaft"]
（）是指产品从厂家到消费者手中经过的所有批零渠道。 ["价差","促销渠道","营销渠道","间接渠道"]
LED灯具产品研发需解决的问题是什么？
The reason why more and more of the large merchant vessels are being powered by medium-speed diesel engines is （）. ["they operate between 150 and 450 rpm","they are connected to the propeller by gearing","their smaller size and weight","they can be connected directly to the propeller without gearing"]
在图层调板中，按住哪个键单击图层前的眼睛图标可以将别的图层都隐藏而仅显示该图层（）。 ["Alt","Ctr","Shift","Ctrl+Shift"]
如何用感官来评价淡水鱼的新鲜度？
