总论
Your performance in the driving test didn't reach the required standard, ____, you failed. A. in the end B. after all C. in other words D. at the same time (全国高考,99-23) 答案为 C。但是, in other words 在句中作什么成分呢?
in other words 应分析为插入语。什么叫插入语呢？插入语就是在语法结构业已完整的句子里插进去的词、短语或句子（后者称作插入句）。插入语的特征是：把它拿掉之后，句子的语法结构和语义仍是完整的，只是缺少了一些表达上的精确性。例如：
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Generally speaking, newspapers follow the American way. 一般说来，报纸采用美国英语的拼法。
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In a word, hunger is a big problem in the world today. 总之,饥饿是当今世界的一个大问题。
如果把上面两句中的插入语 Generally speaking 和 In a word 分别拿掉, 则句子无论在句法上或语义上都是成立的。
从插入语本身的结构来看,用作插入语的主要有:副词、形容词、介词短语、不定式、分词、分句:
A. 副词
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Unfortunately, I missed the last bus. 很不幸,我没有赶上最后一班公共汽车。
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Personally, I'd rather go to the Science Museum. 就我个人来说,我想去科学博物馆。
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Oddly, Da Vinci appears to have forgotten to paint the Cup of Christ. (Dan Brown, The Da Vinci Code) 可奇怪的是，达·芬奇好像忘了把圣杯画上去。（《达·芬奇密码》）
B. 形容词
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If she ran towards it, it might attack her. Worse still, it could even carry off the baby in its mouth. 如果她朝狮子冲过去，狮子也许会咬她。更糟的是，狮子可能把婴儿叼走。
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He passed his exams, and even better, when he left university he had earned enough money to start his own business, offering guide services to tourists. 他通过了考试，而比这更好的是，当他毕业时，他已经赚了一笔钱，足够开始经营自己的导游业了。
C. 介词短语
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To my great joy, the plant did look exactly like what we were looking for. 令我极为高兴的是,这种植物和我们所要找的植物完全一样。
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In other words, I should not watch TV, or look over your shoulder at other people while we are talking together. 换句话说，当我们在一起谈话时，我不应当看电视，也不应当越过你的肩膀瞅别人。
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“Now we know that Clare Flower is dead, does that mean the money will now come to me? After all, I am the only one of my aunt’s relations still alive.” He was smiling hopefully.
“既然我们知道克莱尔·弗劳尔已经死了，那么这是不是意味着这笔钱该归我所有了？要知道，我是我姑妈唯一活在世上的亲戚。”他的脸上露出了希望的微笑。
D. 动词不定式
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To speak frankly, I don't like the idea. 坦白地说,我不喜欢这个主意。
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To conclude, it was a great success. 总之,这是很大的成功。