Characters are a kind of graphic language, much different from languages that use an alphabet such as English. The correct way to tell between them is to remember the structure and meaning of every character, not pronunciation, because there is a very close relationship between meaning and structure of characters. Example: 房(house)=户+方. 房 is a shape-pronunciation character. 户 is for shape and 方 is for pronunciation. 户 means 'door'. 房 means 'A person lives behind a door'. 方 pronunciation is "fang" and tone is 1, and with the tone mark it is written as "fāng". 房 pronunciation is also "fang", but tone is 2, with the tone mark it is written as "fáng".