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

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
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

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
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

when 引导时间状语从句.
which一般引导的是物.
你看前面有个since了么,since表示自从.
since when这并不算什么固定搭配把.