碱―石灰烧结法和拜耳法生产氧化铝需要哪些主要原料？
Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（） ["Control the amount of lube oil burned in the combustion chamber","Transmit heat from the piston to the cylinder liner","Prevent damage to ring groove inserts by acting as a heat dam","Dissipate combustion chamber gas pressure by channeling it through the ring ga"]
新造客车穿线钢管弯曲线弯角不应小于（），弯曲半径处不应有皱折。 ["45°","60°","90°","120°"]
什么是起居甲板？
数字电液调节系统有何优点？由哪几部分组成？
什么是切片纺丝法？
