Who is now commonly used where previously it was only to be considered to be correct to use whom. Who, however, cannot be used directly after a preposition, for example, you cannot say '...the woman to who I spoke'. Instead you can say '...the woman to whom I spoke' or '...the woman I spoke to'. There are some types of sentence in which who cannot be used, for example when you are talking about quantities. ...twenty masked prisoners, many of whom are armed with makeshift weapons.

许多先前只能使用 whom 的地方现在也经常使用 who，但作为介词的宾语只能用 whom。比如不可以说the woman to who I spoke，而说 the woman to whom I spoke 或 the woman I spoke to 。此外还有些情形下不能使用 who，比如在指数量时：twenty masked prisoners, many of whom are armed with makeshift weapons (20个蒙面犯人，其中许多用的是临时凑合的武器)。