这个句子为什么使用过去完成时?I was wondering if you'd ever thought of starting a business.

这个句子为什么使用过去完成时?I was wondering if you'd ever thought of starting a business. i （）,so i didn‘t know where i was 这个句子填was lost.我们应该把它理解成was/were doing过去完成时还是,be+形容词,为什么那么理解请帮助 下面这个句子中为什么要用过去完成时,有什么规律吗?Not until he had accomplished his mission did he realize that he was seriously ill. 过去完成时中肯定句可以使用瞬间动词吗?比如这一个句子正确吗?我本人觉得在意思是没问题的,when I was 10 years old,I had borrowed this book. I——(know) him when I was a student.为什么要用过去完成时? I ——(know) him when I was a student.为什么要用过去完成时而不是一般过去时? the first time i saw it was three year ago要过去式还是过去完成时为什么? when i was young ,i have read the book for many times这个句子对吗?为什么? she said i was hard-working 这个句子中为什么用I而不用me 这个句子为什么要用过去完成时?Work on it had begun before my sisiter left. That was what I thought his answer would be这个句子所使用的语法有那些? I was having a hard time finding the school.这个句子为什么用having I ______there for three days with my parents last month 答案是was 为什么不能用过去完成时had been My (wife was cooking) the dinner while I (was working in the garden).括号里的句子是过去完成时cooking和working 是动词 为什么还要用was 不是应该是助动词吗?额 错了 括号里的句子应该是过去进行时 I want to know what my father ___(was doing/did) when he was my age.为什么选was doing 不选 did我想知道我的爸爸做过什么当他在我这个年龄的时候?这句话是这个意思吗?为什么不用过去完成时呢?做过不是已经 It gave me quite a shock to be told I was seriously ill.为什么to be told前面为什么不加i was怎么理解这个句子结构 过去完成时能否单独使用如题若在一篇通篇用过去时的完形填空里，一个单独的句子（简单句）能否直接用过去完成时？例如：.............I had been there for 2 days。 after he was arrested,the man …after he was arrested ,the man admitted hiding in the box before the plane left London.1.he was arrested为什么不用过去完成时?2.动名词hiding做动词admit的宾语这个规则在任何句子中都通用吗