还有一题请教: OG 181

181. Because of the enormous research and development expenditures required to survive in the electronics industry, an industry marked by rapid innovation and volatile demand, such firms tend to be very large.
(A) to survive
(B) of firms to survive
(C) for surviving
(D) for survival
(E) for firms' survival

Correct Answer: B

请教require的用法：石林语法中指出 require of sb.(sth.) to do sth. 是错的，为什么这里的正确选项采用了这种结构？疑惑呀...

这里考得不是require 用法

the expenditures of firms

the expenditures required to survive

如果把 required to survive 放在 the expenditures of firms 之后的话，required 就修饰 firms 了，表达意义不对。

所以，把 Required 放在 expenditures 之后，修饰清晰。

be required to do， 用的是 require 的被动式。