The number of the people who can afford to buy their own house more than 60% but a number

问题补充：

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

答案：

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。