最新整理（四）！高考英语24语法，带你攻克高中所有语法难点！(6)

Hello! I didn"t know you were in London.How long have you been here?喂！我不知道你在伦敦。你来多久了？
⒉ 表示过去的习惯性或经常发生的动作，常与always，often，usually,seldom等表示频度的副词连用。
如：Then I was in the countryside,I often called on my old friends there.我在乡村里，经常去拜访那里的朋友。
I went to the cinema once a week when I was at school.我上学时每周去看一场电影。
注意：表示过去经常或反复发生的动作，还可用used to 或would加动词原形表示。
如：When I stayed at Aunt Liu"s,she would tell me about the great changes which had taken place in the village since liberation.当我住在刘大娘家时，她常常告诉我解放以来农村发生的巨大变化。
She used to go for a walk after supper,but now she prefers to stay at home.她过去晚饭后总出去散步，但现在她却真欢呆在家里。
⒊ 用来代替过去将来时。
在条件、时间状语从句中，常用一般过去时代替过去将来时。
如：They said they would let us know if they heard any news about him他们说如果听到什么关于他的消息，就通知我们。
He promised that when he went to the bookstore,he would buy me a book.他答应去书店时为我买本书。
He said he would not go if it rained.他说如果天下雨就不去了。
They told us that they would not leave until she came back.他们告诉我们，直到她回来他们才会离开。