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

<unit_n>

<force> <force_word>

<unit_n-not_det-pl>

<force> <force_word-pl>

<vehicle-not_creatable-pl>

<force> <vehicle_id-not_creatable-pl>

<unit_n-sing>

<force> <force_word-sing>

<aircraft-not_creatable>

<force> <aircraft_id-not_creatable>

<flight-not_creatable-sing>

<force> <flight_id-not_creatable-sing>

<item_n-sing>

<force> <loadable_item-sing>

<unit_n-not_det-sing>

<force> <force_word-sing>

<item_n>

<force> <loadable_item>

<vehicle-not_creatable-sing>

<force> <vehicle_id-not_creatable-sing>

<vehicle-not_creatable>

<force> <vehicle_id-not_creatable>

<aircraft-not_creatable-pl>

<force> <aircraft_id-not_creatable-pl>

<flight-not_creatable>

<force> <flight_id-not_creatable>

<flight-not_creatable-pl>

<force> <flight_id-not_creatable-pl>

<aircraft-not_creatable-sing>

<force> <aircraft_id-not_creatable-sing>