since when用法That was in 1929,since______ things have been better._英语解答

since when用法
That was in 1929,since______ things have been better.
A.which B.when
为什么答案选 B when 不选 A which 呢

人气：140 ℃　时间：2019-12-19 02:36:30

解答

这是定语从句,先行词是1929,things have been better中主谓宾俱全,因此1929在句中做时间状语.不是since when的用法