一， 某人花费--------时间做某事
A． It takes sb some time todo sth.
B． It took sb some time todo sth..
C． It will take sb some time todo sth.
二．该做------的时候到了.
A .It is time for sth...
B . It is time to do sth.
C.It is time for sb to do sth.
D.It is time that +从句（从句中谓语动词用过去式或者should+动词原形，time前可加上high或者about，分别表示强调或大概之意，that从句中的that常省略）个
三．自从-------已----
A.It is /has been+时间段+since从句（从句中谓语动词用过去式）
It is /has been three years since we got separated.
B.It was /had beem +时间段+since从句（从句中谓语动词用过去完成式）
It was/had been five years since I had learnt to play chess.
四．某人第--------次做某事
A.It is the first /second /third time that +从句（从句中用现在完成时态）
B.It was the first /second /third time that +从句（从句中用过去完成式）
五．经过-----之后才----
A.It was +时间段+before+从句（从句中谓语动词用过去式）
It was three years before I met him.
B.It will be +时间段+before从句（从句中谓语动词用现在式）
It will be four years before we meet again.
六．没过多久就----
A．It was not +时间段+before从句（从句中谓语动词用过去式）
It was not long before the war broke out.
B.It will not be +时间段+before从句（从句中谓语动词用现在式）
It will not be long before we meet again.