为什么you should understand the traffic rule by now you have had it

题目

为什么you should understand the traffic rule by now you have had it
expiainde often enough 中要用expiainde而不能用to explain

答案

从整个句子分析来看,后面的you have had it explained often enough句中存在这样的句型：have had it explained.忽略掉过去完成时have done结构,我们有have it explained,即have sth done结构,表示某事已经被完成.如...