Most of the guests ________ to the wedding last week were his classmates and friends.

A．having been invited

B．to be invited

C．being invited

D．invited

实验效应具有的特点是（）。

A.精密性、灵敏性、特异性、稳定性

B.精密性、灵敏性、变异性、客观性

C.精密性、灵敏性、变异性、均衡性

D.精密性、特异性、稳定性、客观性

E.灵敏性、变异性、均衡性、稳定性