Common are glucose, maltose, starch and so on.

The origin of the name of carbohydrate is based on biochemists' previous discovery that a class of substances can be written as empirical molecular formula: Cn(H2O)m, and the ratio of hydrogen to oxygen is always 2: 1, so carbohydrates are considered to be compounds of carbon and water. But later discovery proved that many sugars did not conform to the above molecular formula.