If something necessitates an event, action, or situation, it makes it necessary.
例句
A prolonged drought had necessitated the introduction of water rationing...由于持續(xù)干旱，用水需要實(shí)行配給了。Frank was carrying out fuel-system tests which necessitated turning the booster pumps off.弗蘭克在做燃料系統(tǒng)測試，這一測試需要關(guān)掉升壓泵。