A lot of words in Chinese have been shortened into single-syllable, and thus single-character, words. Often times though these single syllable words are not 'clear' enough in speech, in writing though this does not really pose an issue. A second syllable (character) can be added to make things clearer, for example:
已 — 已经
易 — 容易
I suppose we can call these single character words with double character words with same meaning equivalents.
How can we find a single-characters double-character equivalent?