The number of the people who can afford to buy their own house more than 60%,but a number of houses .
A. are; hasn’t been built
B. are; has built
C. is; haven’t been built
D. is; have built
网友回答
A. are; hasn’t been built
B. are; has built
(答案→)C. is; haven’t been built
D. is; have built
解析：考查：The number of +复数名词做主语，谓语动词用单数，a number of +复数名词做主语，谓语动词用复数，故选C。