Sentence-dividing method applied to an audio/video-playing system

This invention is about a sentence-dividing method applied to a audio/video- playing system. The procedures of the method are as follows. Sentence-tag detection: when a multimedia-playing system is running, a subtitle decoder can use the subtitle unit information to detect the beginning and the ending time of a sentence and form a sentence tag. Sentence tag management: a circular buffer is provided in order to save the sentence tag of a sentence in a circular buffer and at the same time, one index is maintained to access the buffer. Sentence tag playing: when the multimedia-playing system is running, the sentence tag of the sentence that is going to be played can be acquired from the circular buffer according to the command outputted from a controller and the sentence is played.