Another feature of Chinese characters and Chinese vocabulary is the existence of 多音字 duōyīnzì, or multiple pronunciation characters. Many characters have more than one pronunciation, and as the pronunciation changes, so does the meaning. These characters are not uncommon, making up from five to 10 percent of commonly used characters. The meaning is almost always clear from the context, so they do not create any particular difficulty. Note that in some instances the difference is the tone; in some the pronunciation is entirely different. Also note that in some instances there are more than two pronunciations.

Examples
好 hǎo good vs. 好 hào to like
乐 yuè music vs. 乐 lè happy
中 zhōng middle vs. 中 zhòng hit (a target)
还 hái still vs. 还 huán return
都 dōu all, both vs. 都 dū capital (city)