强调句式 It is 还是It was?
什么时候用is什么时候用was呢?
我看到这样的例子：
It was my uncle that(who) sent me to the school.
It is the article that we discussed last week.
It is in the room that I was born 30 years ago.
我暂时无法总结出什么状况下用is什么情况下用was.