职称英语重点语法讲解--状语从句

　　Seeing all of the children already seated, he said,“Since everyone is here, let’s start.”

　　(3)下列情况下只能使用because:

　　①在回答why的问句时;②在用于强调句型时;③被not所否定时。

　　4、地点状语从句：where, wherever

　　Make a mark wherever you have any questions.

　　We will go where the Party directs us.

　　5、目的状语从句：that, so that, in order that

　　注意：目的状语从句的谓语动词常与情态动词连用，否则可能是结果状语从句。不可置于句首。

　　6、结果状语从句：that, so that, so … that, such … that …

　　注意：so + 形容词/副词 + that从句;such +　名词 + that从句。

　　7、方式状语从句：as, as if(though)

　　I’ll do as I am told to.

　　It looks as if it is going to rain.

　　8、比较状语从句：than, as

　　9、条件状语从句：if, unless, so (as) long as, in case, once, a far as, on condition that.

　　注意if与unless的区别：不能用and连接两个unless从句，即不能有… unless …,and unless … 。但if … not and if … not却不受此限。

　　You won’t lose your weight unless you eat less and unless you exercise more.(×)

　　但可以说 … unless you eat less and exercise more.

　　10、注意状语从句中从句的省略现象

　　(1)连接词 + 过去分词

　　Don’t speak until spoken to.

　　Pressure can be increased when needed.

　　Unless repaired, the washing machine is no use.

　　(2)连词 +　现在分词

　　Look out while crossing the street.

　　(3)连词 + 形容词/其他

　　常见的有 it necessary、 if possible、 when necessary、 if any等。