Parenthesis(插入语)

　　插入语一般对一句话作一些附加的解释。它们和句子其它部分关系不十分密切，常用逗号和其它部分隔开。常见的有以下两种：

　　1. 短句。常用的有 I think, I hope, I guess, I'm afraid, I believe, I suppose, I wonder, I'm sure, you see, you know, it seems, don't you think/know, it is said, it is suggested 等。这些短句可以放在句末或句中，如：
　　　The first part, it seems, is better written than the other parts.
　　　We'll have to book a single room in advance, I'm afraid.
　　　When do you think they’ll be back?

　　2. 另外一类插入语的语法结构可以是不定式、现在分词（短语）、介词短语、形容词、副词、从句等，其中有些起着承上启下的作用，如：
　　　There were twenty people present, to be exact.
　　　Generally speaking, smoking will harm your health.
　　　Actually, he is only ten years old.
　　　She is not fit for the job, if I may say so.
　　　Most important of all, these activities have strengthened our relationship with the American people.
　　　Besides, we have to consider the storage of food.
　　　As a result, he didn't get the job.
　　　In conclusion, we should try our best to improve the present situation.