锯割薄板或管子，可用（）锯条。
A．粗齿
B．细齿
C．随意
D．中齿
参考答案：B
分解因式 （1）a2（x﹣y）+16（y﹣x）；
（2）（x2+y2）2﹣4x2y2．
—Jane, why are you still here? The party has already begun.
—What? But I _____ about it.[ ]
A. don't tell
B. didn't tell
C. am not told
D. wasn't told
