16. The computer system of claim 14 , wherein each characteristic unit defines, for each of the corresponding series of Chinese expressions, a respective position in the Chinese sentence and a respective relative position of at least one other expression in the series of Chinese expressions.
14. A computer system, comprising: one or more processors; and memory having instructions and a Chinese language punctuation model stored thereon, wherein the Chinese language punctuation model was pre-generated from a training corpus of Chinese sentences having punctuation marks and includes multiple predefined characteristic units, each predefined characteristic unit including a series of Chinese expressions, possible punctuation marks present in the series of Chinese expressions and their respective probabilities, the instructions when executed by the one or more processors cause the processors to perform operations, comprising: extracting a Chinese sentence from a speech input through speech recognition; identifying a plurality of expressions in the Chinese sentence by segmenting the Chinese sentence according to their semantic features, each of the plurality of expressions including one or more Chinese characters; grouping the plurality of expressions in the Chinese sentence into a plurality of characteristic units according to the semantic features of the plurality of expressions using one or more predefined characteristic templates; extracting, from the Chinese language punctuation model, a plurality of possible punctuation marks appearing in the corresponding series of Chinese expressions and their respective probabilities for each of the plurality of characteristic units; determining a punctuation mark and its weight for each of the plurality of expressions in the Chinese sentence according to the plurality of possible punctuation marks extracted from the Chinese language punctuation model; calculating an overall weight for each possible arrangement of punctuation marks in the Chinese sentence based on the weights of punctuation marks at each of the plurality of expressions in the Chinese sentence; and adding the punctuation marks corresponding to an arrangement of a maximum overall weight into the Chinese sentence.