Millimeter millimeter, centimeter centimeter, meter meter, kilometer meter.

Region:

Square centimeter cm? Square decimeter (dm? ), square meters ㎡, hectares ha, square kilometers km? .

Volume:

Cubic centimeter cm? , cubic decimeter dm? , cubic meters m? ，l，ml ml。

Quality:

Grams, kilograms, tons.

Time:

Seconds, minutes, minutes and hours.