—We are planning to have a casual get-together this Saturday or Sunday. Are you coming?

—______. I’ve got rather a busy day this weekend.

A．I hope so

B．Sounds great

C．You’d better not

D．I’m afraid not

阻聚剂和缓聚剂两者（）。

A、无差别

B、有本质差别

C、只在抑制过程上有差别

D、在抑制程度上有差别