most of them还是most of which
请看看下面这道题，答案是 most of them 还是 most of which：
The growing speed of a plant is influenced by a number of factors, |||||| are beyond our control.
A.most of them B.most of which C. most of what D. most of that
【剖析】答案为B。因为两个句子之间没并列连词and，故可排除 A 和 D；又由于 what 不可以用于引导定语从句，所以 most of what 也可排除。此处的 most of which 等于 and most of them，所以若在选项 A 的前加上 and，则也是对的。
比较：
Some managed to vote, but most of them didn’t. 有的人设法投票了，但多数人都没。
The buses, most of which were already full, were surrounded by an angry crowd. 公共汽车大部分都已经挤满了人，它们被愤怒的人群包围着。
