when 引导的时间状语从句

题目

when 引导的时间状语从句
1.when we ___A______,we discovered that the manager had reserved the wrong room for us.A.arrived B.had arrived
2.By the year 2000,12.4%of the us population had reached the age of 65,although this was lower than in 1990 when it ___A_______ at 12.3%.A.had peaked B.peaked
为什么两题不一样?不都是when 引导的从句先发生?

答案

跟when引导没关系.第一题并没有强调when从句先发生,甚至可以理解为是同时的,即,到了就发现……；第二题强调when从句先发生,表示1990年“已经”达到了12.3%.