It was about 600 years ago______the first clock with a face and a_英语解答

It was about 600 years ago______the first clock with a face and an hour hand was made.
A.that B.until C.before D.when
这个题选B.说是强调句.我就想知道为什么不能选D.选D可以是时间状语从句啊

人气：453 ℃　时间：2020-03-27 04:12:15

解答

把句中的it was...that去掉,句子不缺任何成分.：the first clock with a face and an hour hand was made about 600 years ago.如果选when,句子不通顺,about 600 years ago.是由介词构成的时间状语,不能构成状语从句...