Clarification is Zenbo’s behavior of asking user questions to clarify their intention when dialogue information is too little to understand what user means. There are circumstances that provoke Clarification as the followings.
1. Expect to capture certain Belief (known as variables) from user’s utterance, but fail.
2. More than one sentence intents are captured so that Zenbo cannot judge which one it is.
3. Zenbo has found possible intents with similar sentences, but needs further confirmation due to low similarities.