It was lack of money, not of effort, defeated their plan.
A. which
B. as
C. that
D. what
网友回答
A. which
B. as
(答案→)C. that
D. what
解析：整个句子为强调句，被强调成分为 lack of money, not of effort。由于句中插入 not of effort 这一结构，干扰了许多同学对 it was lack of money that defeated their plan 这一强调句的认识和理解。