— Can you come to attend our party tonight?

— Sorry, but I do wish I _____.[ ]

A. could

B. can

C. will

D. had

卵子受精时，阻止多精子入卵有关的机制是______。

A．顶体反应
B．卵子激活
C．精子获能
D．卵质膜反应
E．精卵膜融合