of whom two-thirds与two-thirds of them的区别

问题描述

There are two thousand students in our school, _____are girls.

A. of whom two-thirds                B. two-thirds of them

C. two-third in them                    D. two-thirds which

老师，这题答案是A， 我选了B。我不明白这题为啥A是正确呀？ 麻烦老师帮忙讲解。

谢谢。

老师答疑

刘老师：

There are two thousand students in our school, _____ are girls.

A. of whom two-thirds

B. two-thirds of them

C. two-third in them

D. two-thirds which

▲ 该题的测试目的有两个内容：1.分数表达法； 2.定语从句。

第一个问题不用解释了。第二个问题的关键是，school后面是个“逗号”，不是句号或分号。这说明句子还没完，意味着后面是一个定语从句（非限制性定语从句）。

以下表达都正确，请仔细体会为什么？

1. There are two thousand students in our school. Two-thirds of them are girls.

2. There are two thousand students in our school; two-thirds of them are girls.

3. There are two thousand students in our school and two-thirds of them are girls.

4. There are two thousand students in our school, and two-thirds of them are girls.

5. There are two thousand students in our school, of whom two-thirds are girls.

6. There are two thousand students in our school, two-thirds of whom are girls.

▲ 句1加句号，是两个单句。

句2加分号，表示两个分句。

句3加and，表示两个并列句。

句4多了一个逗号表停顿，跟句3相同。

句5，非限制性定语从句，of whom在前表所属关系，“他们中的”三分之二。

句6，非限制性定语从句，of whom在后表所属关系，“他们中的”三分之二。

▲ them 跟whom 的区别是：前者是人称代词，指代前面提到的名词，但不能充当关系代词引导定语从句。具体地说，前句后面是个逗号，而没有and，这时就要小心了：后面的句子很可能是一个定语从句，在many of, some of, one of, two-thirds of 等这些词组后, 就要用whom了。

曾老师：

这是一个非限制性定语从句，关系代词 whom 指代先行词 students，这里的 of whom two-thirds 也可写为 two-thirds of whom。如果 B选项在 two-thirds of them 之前有个 and 则可以构成并列句。比较：

The police took away four people, one of whom was later released. 警察抓走4个人，其中1个随后被放了回来。

Soldiers took away four people, and one of them was later released. 警察抓走4个人，其中1个随后被放了回来。