The category "<system_operation-user_response-gapsout_null-gapsin_null>" can be expressed as follows:

<system_operation-user_response-gapsout_null-gapsin_null>

<cancel_operation-user_response-gapsout_null-gapsin_null>

<change_grammar_operation>

<display_control_operation-gapsout_null-gapsin_null>