以下两个强调句有何不同?It was a Mexican who bought our old car last wee

以下两个强调句有何不同?It was a Mexican who bought our old car last week.It was
以下两个强调句有何不同?
It was a Mexican who bought our old car last week.
It was last week that we sold our old car to a Mexican.

第一句的引导词是who,用来表示,强调的对象是个人,也就是a Mexican
第二句的引导词是that,在引导词为that时,我们把it is/was ……that 拿掉句子依然成立,所以,句子就变成了 last week we sold our old car to a Mexican.,很明显,是强调时间的了.