你把强调句 It was.that 去掉,还原一下
Not until nearly a month later did I receive the manager's reply.
否定词放句首,倒装
如果把倒装再还原就是
I didn't received the manager's reply until nearly a month later
until nearly a month later,就是时间状语,
你硬要在插个when的状语从句,意思不就不对了吗