话题 It was a Sunday

话题 It (so) happened that…

话题 come to it cold

话题 It is nice doing

话题 it may be that

话题 Who was it that…

话题 Who was it who…

话题 It was后面接复数名词

话题 It doesn’t matter.

话题 it is known that...

问题 that可以代替it作形式主语吗

That isn’t anything for us to be ashamed of.这里的句子为什么用 that 作主语，而不用 it 呢？难道 that 也可以作形式主语吗？

问题 he explained how it was 句子对错

请问老师he explained how it was 对吗？was 后面是不是少成分？如果不对如何改？

问题 主谓一致(It is you who...)

It is you who ____ wrong? You _____ a useful word. A.are;are B.are;is

问题 分析：He is clever enough to do it well.

请分析：He is clever enough to do it well.句中的不定式 to do it well 是什么成分？肯定是状语吧？是什么状语？在什么书上有分析吗？

问题 than necessary or possible是否=than it is necessary

曹老师提到（http://ask.yygrammar.com/q-26040.html），Use too many with countables to talk about more things than necessary or possible.中的than从句=than are necessary or possible（than为主语，对应但不等同于主句的things)He never says more than is necessary.无省略，than...