风口小套主要是受到渣铁与风口的直接接触而烧坏的。（）
参考答案：对
Swimming is my favourite sport. There is ________ like swimming as a means of keeping fit.[ ]
A. something
B. anything
C. nothing
D. everything
机翼升力系数与哪些因素有关？（）.
A、仅与翼剖面形状有关
B、与翼剖面形状和攻角有关
C、仅与攻角有关
D、与翼弦有关
