注意: 1 英寸 等于 2.54 cm  = 25.4 mm  1 foot (feet英尺) = 12 inch (inches英寸) = 30.48 cm
1码 yd = 0.9144 m = 36 inches英寸 (in) = 3 feet英尺 (ft) und 1 land mile = 5280 feet英尺 = 1609.344 m
1 m (meter米) = 10 dm (decimeters分米) = 100 cm = 1,000 mm , 1 cm = 10 mm = 0.1 dm = 0.01 m 多少厘米
1 km (kilometer公里) = 1000 m (meters米) = 100,000 cm (centimeters厘米) = 1,000,000 mm (millimeters毫米)