—Are we going on a field trip to Minghu Lake by bus?

— Yes, but the teacher didn’t say _________.

A. where to go         B. when to go          C. how to go

质粒DNA的特征有（）

A.自我复制

B.赋予细菌产生新的生物学性状

C.可自行丢失与消除

D.能转移

E.相容性与不相容性