sentences: kilometers km are a metric unit used for measuring length / distance generally used for values between 1 and 50000000
docs: one_mile is longer_than_one_kilometer. kilometer is metric_linear_unit. kilometers is metric_unit_of_distance. planet is kilometres_scale_object. continent is kilometres_scale_object. kilometers_and_centigrade is measures_in_meteric_system. kilometer is one_type_of_unit. kilometers_per_hour is rate. unit_of_speed is kilometers_per_hour. kilometers is part_of_metric_system.