The population of this city are not as less as those of yours.are→is；less→little；those→tha

问题补充：

The population of this city are not as less as those of yours.are→is；less→little；those→that

答案：

(答案→)are→is；less→little；those→that

解析：此句共有三处错误：population作主语，谓语用单数；as...as...中间的形容词或副词用原级；population为不可数名词，所以要用that代替。