断离肢体最好在伤后不超过______小时内重建血液循环。
参考答案：6～8
A．通过B点时速度是3m/s
B．通过B点时速度是6m/s
C．AB的长度为12m
D．汽车在AB段和BC段的平均速度相同
Without the invention of the computer, much of today's advanced technology _______.[ ]
A. will not have been achieved
B. would not have been achieved
C. have not been achieved
D. had not been achieved
