ndreds of years.2). Our friendship________ ________ ________ the late 70s.3). This is a law ________ (date) from the 17th century.Keys: 1). dates back 2). dates back to 3). datingРⅤ.重点句子(旨在提供句子结构等所需材料)1. We have been excavating layers of ash almost six metres thick, which suggests that they might have kept the fire burning all winter. 我们一直在挖掘一层层的积灰,几乎有六米厚,这说明他们可能整个冬季都在烧火。[解释]“have been excavating”是现在完成进行时,表示从过去开始一直延续到现在,或将继续延续至将来。如:We have been working on this project for over a month now. 到目前为止,我们一直在处理那个项目,已经花了一个多月时间了。注意:区别现在完成时和现在完成进行时的区别。一般来说现在完成时表示已经完成,而现在完成进行时表示还没完成还要延续下去或者刚刚完成。试比较:They have built a house. (完成) / They have been building a house. (尚未完成)[练习] 在括号里填入所给词的适当形式。1). We ________ ________ (work) for two hours by the time she came.2). Last year he ________ (write) a novel. I don
全文预览
