纠正措施应与已发生不符合的影响相适应。（）
参考答案：对
将自然数1，2，3，…，21这21个数，任意地放在一个圆周上，证明：一定有相邻的三个数，它们的和不小于33．
Suan , you are so lazy.This job ___ hours before.
A．should finish
B．could be finished
C．must have been finished
D．should have been finished
