经焊补后的风机叶轮,应先做动平衡试验,后做静平衡试验
参考答案:错
—Do you believe that paper is made _____ wood?
—Yes, I do. And you can see that books are made _____ paper.[ ]
A. from;from
B. from;of
C. of;from
D. of;of
什么可以使平流雾消散或抬升为低的云层?