more careful,careful 属于多音节形容词,比较级在该词前加more,最高级前加most careful
busy 属于辅音加y结尾的,要变y为i加er,最高级是变y为i加est,因此它的比较级是busier,最高级是busiest
careful, 比较级 要more careful ,最高级the most careful
busy busier busiest
more careful,the most careful
busier,busiest