The category "<response_utterance-discourse_user_response>" can be expressed as follows:

<response_utterance-discourse_user_response>

<nl_command-user_response>

<nlb-not_command_or_system_utterance_or_user_response>

<np-gapsout_null-gapsin_null-not_wh_or_dummy>

<np-gapsout_null-gapsin_null-not_wh_or_gq_or_dummy>

<special>