The rules that use the category "<to_prep>" are:

<withdraw_command-system_utterance-gapsout_np_gap-gapsin_np_gap>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<suppress_by_fire_command-gapsout_null-gapsin_null>

<movement_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null> and <suppress_by_fire_verb> <by_fire_phrase-direct>

<movement_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null> and <suppress_by_fire_verb> <enemy_loc-gapsout_null-gapsin_null> <by_fire_phrase-direct>

<objective_mod-gapsout_np_gap-gapsin_np_gap>

<to_prep> <engagement_loc-gapsout_np_gap-gapsin_np_gap>

<attack_by_fire_command-gapsout_null-gapsin_null>

<movement_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null> and <engage_verb> <enemy_loc-gapsout_null-gapsin_null> <by_fire_phrase-direct>

<movement_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null> and <plain_attack_by_fire_verb> <by_fire_phrase-direct>

<movement_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null> and <plain_attack_by_fire_verb> <enemy_loc-gapsout_null-gapsin_null> <by_fire_phrase-direct>

<fly_command-system_utterance-gapsout_np_gap-gapsin_np_gap>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-gapsout_null-gapsin_null>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_np_gap-gapsin_np_gap>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-command-gapsout_null-gapsin_null-not_with_compass_direction>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-discourse_all-gapsout_null-gapsin_null-not_with_compass_direction>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<fly_command-user_response-gapsout_null-gapsin_null>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_null-gapsin_null-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<withdraw_command-user_response-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-system_utterance-gapsout_null-gapsin_null-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-user_response-gapsout_null-gapsin_null-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<move_mod-gapsout_null-gapsin_np_gap-not_compass_direction>

<to_prep> <point_loc-gapsout_np_gap-gapsin_np_gap> on

<to_prep> on <line_loc-gapsout_null-gapsin_null>

<fly_command-user_response-gapsout_np_gap-gapsin_np_gap>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<objective_mod-gapsout_pp_gap-gapsin_pp_gap>

<to_prep> <engagement_loc-gapsout_pp_gap-gapsin_pp_gap>

<withdraw_command-system_utterance-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<compass_direction-gapsout_null-gapsin_null>

<to_prep> the <cardinal_direction>

<movement_command-command-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<fly_command-gapsout_null-gapsin_null-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<objective_mod-gapsout_null-gapsin_np_gap>

<to_prep>

<fly_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-gapsout_null-gapsin_null-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<bearing_mod-gapsout_null-gapsin_null>

<bearing_adj> <to_prep> <bearing_spec>

<bearing_adj> <to_prep> <point_loc-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-gapsout_null-gapsin_null>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<move_mod-gapsout_pp_gap-gapsin_pp_gap-not_compass_direction>

<to_prep> <point_loc-gapsout_pp_gap-gapsin_pp_gap> on <line_loc-gapsout_pp_gap-gapsin_pp_gap>

from <engagement_loc-gapsout_null-gapsin_null> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<objective_mod-gapsout_null-gapsin_null>

<to_prep> <engagement_loc-gapsout_null-gapsin_null>

<compass_direction-gapsout_np_gap-gapsin_np_gap>

<to_prep> the <cardinal_direction>

<movement_command-command-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<fly_command-user_response-gapsout_null-gapsin_null-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-gapsout_null-gapsin_null-not_with_compass_direction>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<move_mod-gapsout_null-gapsin_null-not_compass_direction>

<to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

from <engagement_loc-gapsout_null-gapsin_null> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<fly_command-system_utterance-gapsout_null-gapsin_null-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<fly_command-user_response-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-user_response-gapsout_null-gapsin_null-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<bearing_mod-gapsout_np_gap-gapsin_np_gap>

<bearing_adj> <to_prep> <bearing_spec>

<bearing_adj> <to_prep> <point_loc-gapsout_null-gapsin_null>

<movement_command-user_response-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<withdraw_command-user_response-gapsout_null-gapsin_null>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-user_response-gapsout_null-gapsin_null>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<fly_command-system_utterance-gapsout_pp_gap-gapsin_pp_gap-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<withdraw_command-user_response-gapsout_np_gap-gapsin_np_gap>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<move_mod-gapsout_np_gap-gapsin_np_gap-not_compass_direction>

<to_prep> <point_loc-gapsout_np_gap-gapsin_np_gap> on <line_loc-gapsout_np_gap-gapsin_np_gap>

from <engagement_loc-gapsout_null-gapsin_null> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<fly_command-system_utterance-gapsout_np_gap-gapsin_np_gap-not_with_compass_direction>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-user_response-gapsout_np_gap-gapsin_np_gap>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-command-gapsout_np_gap-gapsin_np_gap>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<fly_command-gapsout_null-gapsin_null>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<compass_direction-gapsout_pp_gap-gapsin_pp_gap>

<to_prep> the <cardinal_direction>

<withdraw_command-system_utterance-gapsout_null-gapsin_null>

<withdraw_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<fly_command-system_utterance-gapsout_null-gapsin_null>

<fly_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<movement_command-system_utterance-gapsout_null-gapsin_null>

<movement_verb-system_utterance_or_user_response> <to_prep> <point_loc_np-system_utterance_or_user_response-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>

<movement_command-discourse_all-gapsout_null-gapsin_null>

<report_verb> <to_prep> <engagement_loc-gapsout_null-gapsin_null>

<report_verb> <to_prep> <point_loc-gapsout_null-gapsin_null> on <line_loc-gapsout_null-gapsin_null>