分组选配
参考答案：
将各个装配件的制造公差扩大数倍达到可经济加工的程度，装配时将零件按原公差分组并按相应组进行装配，以保证规定装配精度的方法。
脑充血期大约持续时间是（）
A.20秒
B.5分钟内
C.5～8分钟
D.超过5分钟
E.30分钟左右
1 saw a woman running toward me in the dark. Before I could recognize who she was, she had run back
in the direction she had come. [ ]
A．of which
B．by which
C．in which
D．from which
