牙嵌式离合器在高速时结合困难有冲击，因此适用于转矩不大的低速场合。（）

单项选择题矿物抗风化能力的强弱顺序是（ ）。 A、橄榄石 B、橄榄石>辉石>角闪石>黑云母 C、橄榄石>角闪石>辉石>黑云母 D、橄榄石<黑云母<辉石<角闪石

单项选择题（13）、What did the author constantly fight against while doing her Ph.D. and post-doctoral research? A、A.Lack of confidence in succeeding in space science. B、B.Unfair accusations from both inside and outside her circle. C、C.People's stereotyped attitude towards female scientists. D、D.Widespread misconceptions about nature and nurture