贾谊在《过秦论》中说：“及至始皇，奋六世之余烈，振长策而御宇内，吞二周而亡诸侯，履至尊而制六合。”秦始皇为能够“制六合”而采取的有效措施是

A．以郡县制代替分封制

B．统一文字

C．统一货币

D．统一度量衡

— Have all the students known our class will visit the zoo next week?

— Yes, every student             about it. [ ]

A. has told

B. is told

C. has been told

D. have been told