我认为选 B 和 D 都可
by that time 和 by which time 都有 "届时" "之前“ 之意.
另一同义词是 by then.
by xxx 表示事情已经发生了.
that 和 which 是代词,用来显示关系,意思是 这(个),那(个) .
如 the house in which I once lived 我从前住过的房子.
但 by which time 是比较习惯用法.
我认为选 B 和 D 都可
by that time 和 by which time 都有 "届时" "之前“ 之意.
另一同义词是 by then.
by xxx 表示事情已经发生了.
that 和 which 是代词,用来显示关系,意思是 这(个),那(个) .
如 the house in which I once lived 我从前住过的房子.
但 by which time 是比较习惯用法.