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
网友回答
A. most of them
(答案→)B. most of which
C. most of what
D. most of that
解析：考查定语从句中的非限制性定语从句。题干含义是：植物的生长速度受大量因素的影响，其中的大多数是不受控制的。在非限制性定语从句只能用which，只有which可以在前面用介词，这些是that所不能做到的。而选C答案，what引导后面的是名词性从句，相当于一个名词，显然是不对的。