Question

he stayed there for quite a long time,during_____he learned much spoken english.横线上答案

he stayed there for quite a long time,during_____he learned much spoken english.横线上答案给的是which time,可是为什么不填which？which time不是与前面which所指代的a long time重复了吗？请高手详解
？？？

Answer 1

非限定性定语从句，which 指代前半句的意思，
但是这样的话也翻译不通
during which time ,在句子中做的是状语，只不过是把状语放在主句后面，并且用逗号隔开。

Answer 2

which 是正确的，which time是错误的，给的答案错了！别分析得这么复杂了！

Answer 3

he stayed there for quite a long time,during_which time____he learned much spoken english.
表强调。