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（B）

(E) for firms’ survival

The subject of the main clause (such firms) presumes a prior reference to the firms in question. Furthermore, the logical subject of to survive and the logical complement of required should be made explicit. All three demands are met by B, the best choice. Choices A, C, and D, with no reference to the firms in question, meet none of these demands. In choice E, the illogical and awkward use of a prepositional phrase (for firms’ survival) buries the needed initial reference to firms in a possessive modifier.

require 的用法：

1.require sb to do

2. require of sb that 从句（虚拟语气）

3.require  that 从句（虚拟语气）

require of sb to do 的用法是错的，这句话怎么理解？

本题根据后面such firms,肯定前面要有相应的 reference to the firms,可以直接选A.

对于A本人开始也有与你相同的疑问,就是required这里是过去分词表被动,想不出of firms在这里的成分.请高人祥解

1, require sth. of sb.
对某人有...的要求
2, require sb. to do sth.
要求某人做某事

The expenditures  are required of firms to survive  in the electronics industry. 是用法1的被动形式。to survive  可以理解成firms的定语，也可以理解成目的状语，可能作为定语更好。