短語詞組短語features selecting and extracting 特征選取mixed features extracting method 混合特征提取morphological features extracting 形態(tài)特征提取features extracting techniques 特征提取features extracting and selecting 特征提取與選擇extracting features 特征提取combined extracting features 聯(lián)合提取特征extracting irregular features 不規(guī)則特征提取extracting of features 特征提取 返回 features extracting