Question

Mr.Smith will move into his new house next Sunday,____it will be completely finished.

A.on that time B.by which time C.on which D.by the time 麻烦问下为什么选择by which time,on which不行吗?

Answer 1

on which后面有time的话，也勉强是可以的。
可是没有，所以只能用by which time
希望可以帮助到你。

Answer 2

这里之所以选择by which time,是考察了by the time（到什么时候为止）在非限定性从句中的使用，从句中的the要换做which，whitch用来引导非限定性定语从句。

Answer 3

which time 指代的是next Sunday
by+时间名词。意为：在…之前。
by which time 指的是：在下周日之前

Mr.Smith will move into his new house next Sunday,by which time it will be completely finished.
斯密夫先生下周日就会搬进他的新家了，下周日之前那房子将会全部竣工。

Answer 4

这是习惯用法，如果有at that time 也可以选。

Answer 5

by有到……时候的意思，到新房子装修完毕，到那时候史密斯先生就会搬进他的新家。