Unit 6 单元语法知识梳理-辅教资料-人教版八年级英语下册23页

一、unless引导的条件状语从句 unless是连词，引导条件状语从句，意为“除非……；如果不……”，常引导真实条件句，有时也可引导非真实条件句。unless引导的条件状语从句中的谓语动词常用一般现在时代替一般将来时，主要用于下列情况： 1.主句为肯定句： 例句：Unless some extra money is found，the theatre will close.要是不能额外弄一些钱，剧院将要关闭。 Youll fail in chemistry again unless you work harder.如果你不再加把劲，你化学考试还会不及格。 2.主句为否定句： 例句：One cant learn a foreign language well unless he studies hard.不下苦功夫是学不好外语的。 I will not go unless I hear from him.如果不收到他的来信，我就不去。 unless与if … not unless与if … not连接条件状语从句时，通常可互换 Ill go there unless it rains.= Ill go there if it doesnt rain.我会去那儿，除非下雨（如果不下雨，我就去那儿）。 只能用if … not的情况表示“由于未发生B而发生A”时 Id be glad if she doesnt come this evening.如果今天晚上她不来，我将很高兴。 引导虚拟条件句时If she werent so silly，she would understand.如果她不那么傻，她就会明白了。 二、as soon as引导的时间状语从句 as soon as引导时间状语从句，意为“一……就……；刚……就……”。 例句：As soon as I got to the bus stop，the bus started.我刚到公共汽车站，汽车就开了。 I will write to you as soon as I get there.我一到那儿就给你写信。 含有as soon as引导的时间状语从句的复合句时态搭配： 主句一般将来时，从句用一般现在时表示将来 I will tell him the news as soon as he comes back.他一回来，我就告诉他这个消息。 主句为一般过去时，从句也用一般过去时 He took out his English book as soon as he sat down.他一坐下，就拿出他的英语书。 三、so… that…引导的结果状语从句 so… that…意为“如此……以至于……”，引导结果状语从句，其句型为：主语+谓语+so + adj./adv.+ that从句。 例句：He was so angry that he couldnt say a word.他如此生气以至于说不出话来。 The boy ran so fast that I couldnt catch him.这男孩跑得太快，我赶不上他。 “如此……以至于……”集锦： （1）so+形容词+a(an)+单数名词+ that从句 = such+a(an)+形容词+单数名词+ that从句 例句：It was so fine a day yesterday that we all went out for a picnic.= It was such a fine day yesterday that we all went out for a picnic.昨天天气很好，我们都出去野餐了。 （2）such+形容词+复数名词/不可数名词+ that从句 例句：They are such good students that the teacher likes them.他们都是很好的学生，老师喜欢他们。 It was such fine weather yesterday that we went swimming.昨天天气很好，我们去游泳了。 （3）当名词前有many，much，few，little等词修饰时，只能用so… that…，即so many/much/few/little+名词+ that从句。 例句：There was so much work to do that everybody got bored.有这么多工作要做，人人都感到厌烦了。 There was so little water in the jar that it was not enough for all of us.坛子里的水太少，不够我们所有人用的。