it may be so in theory ,but how will it work ___?
问题描述：
it may be so in theory ,but how will it work ___?
a in existence b in advance c in turn d in practice
说明原因
答
D 理论上讲得通,但实际上怎么做呢?
in practice 实际上
in existence 存在,现有
in advance 提前
in turn 依次,轮流