1. Twenty centimeters are equivalent to two decimal centimeters, as "centimeter" is an outdated term for the metric unit of length, which is still recognized as equal in value. 2. In ancient China, the "centimeter" was a measurement unit derived from the market system. When the metric system was introduced, the term "centimeter" was adopted to facilitate understanding and differentiation. 3. With the advancement of time, these old terms have been standardized, and the symbol "cm" is now commonly used to represent the centimeter, its international symbol. 4. Therefore, "twenty centimeters" is actually a synonym for "20厘米," with no need for conversion between the two, as they are directly interchangeable.