光合作用的碳同化有哪些途径？试述水稻、玉米、菠萝的光合碳同化途径有什么不同？
The function of lubricating oil is to （）. reduce friction between moving surfaces。 provide even distribution of bearing wear。 reduce the accumulation of harmful detergents。 maintain a constant oil temperature output at each beating。
（）可减弱水击的影响。 要缓慢地开关阀门，以减小水击压强。 快速开关阀门，以减小水击压强。 设计时要尽可能增加变头和变径。 输送介质时的压力不能太高。
An American Shipowner can（）in an American port any ship in the same ownership as the one with which he has collided，in spite of the fact that the collision may have occurred in some distant part of the world. attack。 attach。 attain。 attend。
In a flash distilling unit, evaporator feed (seawater) first absorbs heat in the （）. vapor feed heater。 air ejector condenser。 saltwater heater。 distillate cooler。
下列采油新技术中，（）可对区块上多口井实现共同增产的目的。
