The rules that use the category "<n-pl-unit>" are:

<np-gapsout_null-gapsin_null-unit>

<discourse_det-pl> <n-pl-unit>

<np-gapsout_null-gapsin_null-unit-not_wh_or_gq_or_dummy-pl>

<discourse_det-not_wh_or_gq_or_dummy-pl> <n-pl-unit>

<n-proper_name-unit> <poss> <n-pl-unit>

<np-gapsout_null-gapsin_null-unit-not_wh_or_dummy>

<discourse_det-not_wh_or_dummy-pl> <n-pl-unit>

<np-gapsout_null-gapsin_null-unit-not_wh_or_gq_or_dummy>

<discourse_det-not_wh_or_gq_or_dummy-pl> <n-pl-unit>

<np-gapsout_null-gapsin_null-unit-not_wh-pl>

<discourse_det-not_wh-pl> <n-pl-unit>

<n-proper_name-unit> <poss> <n-pl-unit>

<np-gapsout_null-gapsin_null-unit-not_wh_or_dummy-pl>

<discourse_det-not_wh_or_dummy-pl> <n-pl-unit>