在Never before_____in greater need of modern public transport than it is today中,为什么用现在完成时的has this city been.而在Never before_____see such a terrible car accident on the road中用过去式did I。
Never before_____has this city been in greater need of modern public transport than it is today.
"Never before"指的是“从过去到现在说活时的一段时间以来没...”所以用现在完成时,也便于两段时期进行对比;且时间状语Never before 置于句首,后面部分需要部分倒装。
Never before_____did I see such a terrible car accident on the road.