necessary

必须的

【逻】必然的

强制的; 必须做的, 非自愿的

necessary指“必要的”、“迫切需要的”, 如:

essential指“必需的”、“不可缺少的”, 如:

indispensable指“必要的”、“必不可少的”, 如:

vital意为 “非常重要的”、“极需的”, 如:

necessary

needed to achieve a certain desired effect or result; required

resulting from necessity; inevitable

(of a statement, formula, etc) true under all interpretations or in all possible circumstances.(of a proposition) determined to be true by its meaning, so that its denial would be self-contradictory.(of a property) essential, so that without it its subject would not be the entity it is.(of an inference) always yielding a true conclusion when its premises are true; valid.(of a condition) entailed by the truth of some statement or the obtaining of some state of affairs.See sufficient

(in a nonlogical sense) expressing a law of nature, so that if it is in this sense necessary that all As are B, even although it is not contradictory to conceive of an A which is not B, we are licensed to infer that if something were an A it would have to be B

compelled, as by necessity or law; not free

See necessaries