重庆卷高考英语有这样一道题：
John invited about 40 people to his wedding, most of ______ are family members.
A. them B. that C. which D. whom
此题答案是D，但许多同学弄不明白，为什么不能选A呢？most of them不是很常用的表达吗？
其实要区分是选A还是选D，或者说是用most of them还是most of whom，关键问题是要弄清此句是并列句还是复合句。如果是复合句，才有可能包含定语从句，同时也才有可能选用most of whom；如果是并列句，就不可能包含定语从句，同时也不可能选用most of whom，而应选用most of them。所以判断是用most of them还是most of whom的关键是要先判断句子是并列句还是复合句，而判断是并列句还是复合句的关键就是看句中（即两个主谓结构之间）是否有并列连词（尤其是and, but）。
下面就高考英语针对定语从句与并列句考点可能涉及的表达和句式作一归纳。
1. both of them还是both of which (whom)
假若必须在both of them和both of which (whom)之间作出选择，判断方法如下：如果是并列句（两句之间必须有并列连词），用both of them；如果是含有定语从句的复合句（两句之间不能有并列连词），用both of which (whom)；其中的which与whom的区别是看先行词是指人还是指物。比较：
She has written two novels, and both of them have been made into television series. 她写了两本小说，均已被拍成了电视连续剧。（两句间有并列连词and，故用both of them）
She has written two novels, both of which have been made into television series. 她写了两本小说，均已被拍成了电视连续剧。（两句间没有并列连词，故用both of which）
类似both of them还是both of which (whom)这类结构是近年来高考英语考查定语从句时最重要的考点（而不是最重要的考点“之一”），与此类结构相似的还有很多，如其中的both也可以换成one, two, three, some, any, many, several, most, either, neither, all, none等。例如以下各例均为含有非限制性定语从句的复合句，因为两个主谓结构之间没有并列连词：
Both teams made some wild guesses, none of which were right. 两个队都是瞎猜一通，没有猜对一个。
Thompson had two strategies, neither of which seems to have worked very well. 汤普森有两套行动计划，效果似乎都不太好。
They produced two reports, neither of which contained any useful suggestions. 他们作了两个报告，都没有什么有用的建议。
We’ve tested three hundred types of boot, none of which is completely waterproof. 我们已经测试过300种靴子，没有一种是完全防水的。
The factory used 65 percent of the raw materials, the rest of which were saved for other purposes. 该工厂使用了65%的原材料，其余的原材料被节省下来用作其他用途。
English is a language shared by several diverse cultures, each of which uses it somewhat differently. 英语是一种被数个不同文化分享的语言，每种文化运用英语都会多少有些不同。
The growing speed of a plant is influenced by a number of factors, most of which are beyond our control. 植物生长的速度受到多种因素的影响，其中的大多数（因素）都不受我们控制。
说明：若以上各句的逗号后加上并列连词and，那么其后的of which就应改为of them。
2. in that case还是in which case
假若必须在in that case和in which case之间作出选择，判断方法如下：如果是并列句（两句之间必须有并列连词），用in that case；如果是含有定语从句的复合句（两句之间不能有并列连词），则用in which case。例如以下各例均为含有非限制性定语从句的复合句，因为两个主谓结构之间没有并列连词：
Of course it may rain, in which case we'll have to hold the ceremony indoors. 当然可能会下雨，如果那样的话，我们就只能在室内举行仪式了。
She may have missed the train, in which case she won’t arrive for another hour. 她可能没赶上火车，要是那样的话，她可能还等一个小时才会到。
He won’t want to eat it unless he’s really hungry, in which case he’ll eat almost anything. 除非很饿，否则他不会吃东西，一旦饿了，他几乎什么都吃。
说明：若以上各句的逗号后加上并列连词and，那么in which case就应改为in that case。
与此类问题相似的还有at that time与at which time, at that point与at which point, by that time与by which time, for that work与for which work等，道理是一样的。例如以下各例均为含有非限制性定语从句的复合句，因为两个主谓结构之间没有并列连词：
The film started to get very violent, at which point I left. 那部电影看着看着出现了极残暴的场面，我立刻就走了。
The postman comes at 6:30 in the morning, at which time (=when) I am usually fast asleep. 邮递员早晨6点30分来, 这个时候我通常还睡着大觉呢。
The search will not begin until dawn, by which time it will probably be too late. 搜索等到黎明才开始，到那时很可能会太晚了。(http://ask.yygrammar.com/)
The picking of the fruit, for which work they receive no money, takes about a week. 采摘水果这项工作没有报酬，大约耗时一周。
说明：若以上各句的逗号后加上并列连词and，那么其中的which就应改为that。
3. since then还是since when
假若必须在since then和since when之间作出选择，判断方法如下：如果是并列句（两句之间必须有并列连词），用since then；如果是含有定语从句的复合句（两句之间不能有并列连词），用since when。例如以下各例均为含有非限制性定语从句的复合句，因为两个主谓结构之间没有并列连词：
That was in 1949, since when things have been better. 那时是1949年，从那以后情况就好些了。
They left on Monday, since when we have heard nothing. 他们是星期一走的，从那以后我们就没听到什么消息了。
The book was written in 1946, since when the education system has witnessed great changes. 这本书写于1946年，从那时起教育系统就发生了巨大的改变。
说明：若以上各句的逗号后加上并列连词and，那么since when就应改为since then。
与此类问题相似的还有by then与by when等，道理是一样的。如：
Jane is back in May, by when the new house should be finished. 简5月份回来，到那时新房子就会完工了。
The baby is due in May, by when the new house should be finished. 宝宝的预产期在5月，那时新房子应该建好了。
说明：若以上各句的逗号后加上并列连词and，那么by when就应改为by then。
4. that’s why还是which is why
假若必须在that’s why还是which is why之间作出选择，判断方法如下：如果是并列句（两句之间必须有并列连词），用that’s why；如果是含有定语从句的复合句（两句之间不能有并列连词），用which is why。例如以下各例均为含有非限制性定语从句的复合句，因为两个主谓结构之间没有并列连词：
Simon loves you, which is why he wants to be with you. 西蒙很爱你，这就是他想与你在一起的原因。
My usual train was cancelled, which is why I’m so late. 我经常乘坐的那列火车取消了，所以我迟到了。(www.yygrammar.com)
Dust particles must have got into the motor, which is why it isn’t working properly. 一定有灰尘落到发动机里去了，这就是它不能正常工作的原因。
A skilled workforce is essential, which is why our training program is so important. 熟练的劳动力非常必要，这就是我们的培训计划为什么如此重要的原因。
I’m afraid he’s more of a talker than a doer, which is why he never finishes anything. 与其说他是个实干家，不如说是个空谈家，这就是他什么事都永远干不成的原因。
说明：若以上各句的逗号后加上并列连词and，那么which is why就应改为that is why。
（责任编辑 陈根花）