目 录 上一节 下一节 
（当我开车回家时，肯定九点左右了，因为天已全黑了。） 2.He fell asleep immediately last night; he must have been very tired. （昨天晚上他躺下就睡着了，他一定是很累了。） 3.You needn't have done all those calculations! We have a computer to do that sort of thing. （你没有必要做这些计算！我们有计算机来做这种事情了。） 4.Mary couldn't have received my letter; otherwise she would have replied before now. （Mary不可能收到我的信，不然她早就给我回信了。） 5.Comrade Li can't be in Beijing because I saw him in town only a few minutes ago. （李同志不可能在北京，因为几分钟前我在镇里看见他。） 
（你答应过给她回信，你几天前就应该写了。） 7.Must I get everything ready before they come? （我必须在他们来到之前就要做好一切准备吗？） 8.It's quite early. We needn't worry about the time. （还早呢。我们用不着担心时间。） 9The road can be blocked[ 封堵].（道路可能堵塞。）
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