内锥孔为3号莫氏锥度,外圆锥为4号莫氏锥度为()号钻套。
A.1
B.2
C.3
D.4
参考答案:C
Young people are under great pressure. Therefore, parents shouldn’t expect too much from them, for it will only cause pressure to ____________.
A.pick up
B.turn up
C.break up
D.build up
分馏法原油稳定装置如塔顶温度升高,塔顶产品中难挥发组分含量增加,产品质量()。
A.下降
B.提高
C.不变
D.不稳定