It is/was +段时间 +连词（since/before）+一般现在时,一般过去It is/was +段时间 +连词（since/before）+一般现在时,一般过去时,或完成时.请哪位懂的讲一下,关于连词的固定句型

It is/was +段时间 +连词（since/before）+一般现在时,一般过去It is/was +段时间 +连词（since/before）+一般现在时,一般过去时,或完成时.请哪位懂的讲一下,关于连词的固定句型 有没有it is been+段时间+since和it was be+段时间+before这种表达? same,it,to,is,be,the,good连词成段 英语：it was＋段时间＋before结构是什么意思? 英语翻译it is/was 一段时间 +beforeit is/was 时间点 +whenit is/was 一段时间+ since 连词成句 is it mary's book english not this,is,it,jacket,what's,a(连词成句) jacket is it Helen’s(连词成句) children's,it,bedtime,is(.)连词成句 用Children’s it bedtime is连词成句 It is +段时间＋since+主语＋did.请比较：It was +段时间＋since+主语＋had done.如：It is five years since he left here.他已经离开这儿五年了.It was five years since he left here.（同上） 请问第二句不是应该用it when is it 回答：It's on ......还是It's ......It's on + 时间 还是It's + 时间？ 连词成句 green a it was egg you caterpillar white now it's a 强调句it is（was) .that/who,其中it is（was)能不能写成it's/it was不能缩写么? 连词成句 wet,today,is,it,was,but,yesterday,wetter,it wet,today ,is,it,was,but,yesterday,wetter,it连词成句 用下面这些单词连词成句wet,today,is,it,was,but,yesterday,wetter,it was a green caterpillar is it a brown cocoon it 连词成句