Will was stupefied with exhaustion, and he _____ his head on the grass under one of the trees and slept, but he saw a cat acting strangely. 

A．should have lied

B．ought to have lay

C．might have laid

D．must have laid

人力资源需求预测的常用方法有( )。

A．经验估计法

B．比例趋势分析法

C．经济计量模型法

D．劳动定额法

E．德尔菲法