GWD30 verbal20

Q20:

Researchers have announced that the magnetic fields emitted by one manufacturer’s security surveillance system, of which type there are 200,000 worldwide, can interfere with pacemakers and that this interaction can bring on missed or irregular heartbeats, nausea, breathlessness, dizziness, and even fainting.

1. of which type there are 200,000 worldwide, can interfere with pacemakers and that
2. of which, worldwide, there are 200,000 of that type, and which can interfere with pacemakers, and
3. of which type there are 200,000 worldwide, they can interfere with pacemakers and
4. 200,000 of which type exist worldwide, interfering with pacemakers, and
5. 200,000 of that type existing worldwide and can interfere with pacemakers, and

答案选D，我选A。大家觉得呢？

ABC中的there be 有问题：1.不简洁:数字+of which非限结构更简洁

                        2.there be 是表示自然存在的事物，而题目中说的是人为导致的magnetic fields，并非自然存在的。

E：数字+of that错误表达非限表达形式

非限定性定语从句的结构：名词/代词/副词+of+which/whom

例如：one of whom

      400 of which

不知道LZ明白了没，不懂继续问哈