which用法The 6.3-magnitude earthquake was the second in five m

hello,
只要把握好了which,就能消除困惑.
示例：
This is the city where/in which I met John.此处的which指the city,去掉in,the city 就变成了主语,跟之后的I产生主语冲突,一山不容二虎就是这个道理,去掉in后,大致是这个样子的
1.This is the city which held the Olympic Games.
当the city不再是主语时,是这样的
2.This is the city in which the Olympic Games was held.
它的原型是这样的,
3.The Olympic Games was held in this city.
鉴于本人水平有限,再举恐有疏漏,不能自圆其说,故仅举一例,举一反三即可