过去将来时表示在过去预计将要发生的动作或存在的状态.
\x09①过去将来时由“助动词should(第一人称)或would(第二、三人称)+动词原形”构成.在美国英语中,过去将来时的助动词一律用“would +动词原形”.
\x09②过去将来时常由于宾语从句中,时间状语有：later,soon,the next (day).
\x09③在时间状语从句和条件状语从句中不可以使用过去将来时,而应该使用一般过去时.如：He promised that he would pay me a lot if I helped him with the project.(他答应付给我许多钱如果我帮助他搞那个项目)/ Every time when he was free,he would sit down and read some books.(每次只要他有空他就会坐下来看看书)
\x09④表示纯粹的将来时用would或should,表示打算或主观认为的事情用was/were going to (+动词原形).如：She told me she would be 18 the next month.(她告诉我她下个月就18岁了)/ She told me that she was going to have a walk with her pet dog.(她告诉我她打算带她的宠物狗去散步)
\x09⑤过去将来时还可以表示一个过去经常性的动作.如：When it rained in the day,he would bring an umbrella with him.(白天下雨时他会随身带一把雨伞)
