下列孔加工中,()孔是起钻孔定位和引正作用的。
A、麻花钻
B、中心钻
C、扩孔钻
D、锪钻
参考答案:B
—The weather is too cold ______ March this year.
—It was even ____ when I came here years ago.
A.for, colder
B.in, cold
C.in, hot
D.for, hotter
色彩的亮度与光的()和()有关。