sentences: centimeters cm are a metric unit used for measuring length
docs: cubic_millimeter is metric_capacity_unit. meter is metric_linear_unit. millimeter is metric_linear_unit. mass_unit is unit_of_measurement. temperature_unit is unit_of_measurement. decimeter is metric_linear_unit. centimeter is metric_linear_unit. inches_and_centimeters is both_measurements. microgram is metric_weight_unit. centner is metric_weight_unit.