The factory produced a great number of computers most of shipped to foreign countries.A.

问题补充：

The factory produced a great number of computers, most of shipped to foreign countries.

A. them

B. which

C. it

D. what

答案：

(答案→)A. them

B. which

C. it

D. what

解析：考查独立主格结构。这道题容易被认为是一个非限定性定语从句，若在shipped前面加上were 则选which。Most of them shipped to foreign countries 实际上是一个独立主格结构。选A。