Question

求教英语高手,下面哪些句子需要加逗号?哪些不用加?请详细解释,谢谢!

1.I have three telephones for different countries. My telephone for the U.S. is an iPhone.
2.He can’t go through the normal security machines because of his heart which had a quadruple bypass operation last year.
3.The apartment where he lives is very posh.
4.The teacher who I have for grammar said that we’d have a midterm exam tomorrow.
5.Dr. Park who I have for grammar said that we’d have a midterm exam tomorrow.
6.Lake Michigan which touches Chicago gives the city a big advantage in transporting business goods.
7.The lake by my house freezes during the winter.

Answer 1

需要加逗号的句子有：
2. He can’t go through the normal security machines because of his heart, which had a quadruple bypass operation last year. （他的心脏是独一无二的，这种情况下定语从句前要加逗号，使之成为非限制性定语从句。）
5.Dr. Park, who I have for grammar said that we’d have a midterm exam tomorrow. （先行词Dr. Park是专有名词，也是独一无二的，因此定语从句前也要加逗号，使之成为非限制性定语从句。）
6.Lake Michigan, which touches Chicago, gives the city a big advantage in transporting business goods.（原因同上，Lake Michigan是专有名词。）

1和6：共有三个句子，都是简单句，没有任何并列或从属关系，因此句子中间不需要加逗号。

3和4：当定语从句与其先行词关系密切，如果去掉后句子不通、句子的意思不清楚、不完整就要用限制性定语从句。因此两个句子中的定语从句都必须是限制性的，从句前不能加逗号。

Answer 2

都不用加逗号就已经是很正常的定语从句了……

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