The most common cause of lowering the crankcase lube oil flash point is （）. more water contents。 contamination with fuel oil。 higher temperature。 sufficient cooling of oil mist。
明治维新后，日本独特的商品也开始远销欧洲。其中主要的三大商品是（）。 生丝。 瓷器。 浮世绘。 茶叶。
简述乱笺的恢复原则？
The mechanical efficiency of an engine （） because losses occur in the form of friction. is always less than 100%。 is always more than 100%。 is always equal to 90%。 is always less than 90%。
简述组织液循环障碍的发病机理。
Which vessel may show three lights in a vertical line，the top and bottom being red and the middle being white? （）
