3. The method of claim 1 , wherein building the classifier comprises generating a plurality of clusters, each of the plurality of clusters comprising at least one partial set of words, each of the at least one partial set of words including a set of words from the beginning of the speech recognition result to the end of question part of the speech recognition result.
3. The method of claim 1 , wherein building the classifier comprises generating a plurality of clusters, each of the plurality of clusters comprising at least one partial set of words, each of the at least one partial set of words including a set of words from the beginning of the speech recognition result to the end of question part of the speech recognition result. 4. The method of claim 3 , wherein in response to receiving the recognition-stage speech recognition result incrementally in a word by word manner as an input, the classifier calculates a similarity between the input and the plurality of clusters and returns the corresponding end of question part for the recognition-stage speech recognition result based the similarity between the input and any of the plurality of clusters being less than a predetermined threshold.