It was______the morning of last Saturday that we went to visit the organic farm.

问题描述:

It was______the morning of last Saturday that we went to visit the organic farm.
in
on
at
by
选哪个呢?为什么不能选in呢?不是In the morning?

答案为on.
一般来说用in the morning,但是如果有修饰词时,往往用on.
例如:on a winter morning