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

<establish_base_of_fire_command>

<set_up_verb> <base_of_fire_phrase> <location_prep> <engagement_loc> <open_fire_verb> <on_order>

<open_fire_command_1>

<open_fire_verb>

<open_fire_verb> <on_prep> <enemy_loc>