OG118

OG1181l8.  The question of whether to divest themselves of stock in companies that do business in South Africa is particularly troublesome for the nation’s 116 private Black colleges because their economic bases are often more fragile than most predominantly White colleges.

(A) than

(B) than those of

(C) than is so of

(D) compared to（B）

(E) compared to those of

为什么在AB中选择了B，B中加了THOSE OF ，一般都说有THOSE出现是指待错误。

比较的两个事物应该合理，且省略的时候要以不产生歧异为标准， 如果不加those of，则是black colleges's economic bases 与 white colleges比较，即 base 与 colleges 比较，意思上不合理，只能是base与base比较，所以加上了thoes of代指base of

对于南非的116所黑人学院来说，是否放弃公司的股份是个棘手的问题，因为他们的经济基础比起占主导地位的白人学院来说更加的脆弱