what is the probable reason why the population in Kansas began to grow A. Its attitude towards slavery. B. Its cheap land. C. It has climate suitable for farming. D. Its advanced railroad system. 参考答案:A 答案解析:文章提到,自从1861年堪萨斯州作为反对奴隶制度的自由州加入联邦之后,该州的人口开始增加。因此可以推断出是它对奴隶制度所持的态度吸引了大量外来人口,从而使整个州的人口总量增加。
第27题: [单项选择]Generally speaking,the air pollution in cities is more serious thanin the country.
A. ones B. one C. that D. those 参考答案:C 答案解析:对比结构中,对比对象中出现的重复名词用that或those代替,由此排除A项和B项。the air pollution是不可数名词,排除D项。故选C。