necessityn.需要；必需品；必然necessity ties of existence生活必需品necessity of confidentiality[法] 必要信任necessity/non-necessity必要性/非必要性necessity and the feasibility必要性与必然性necessity of cause and cffect因果必然性necessity of scientific norms科学规范的必然性necessity of self-protection[法] 必要自卫, 正当自卫Necessity caused me to come.我不得不来。Necessity mothers invention.需要会产生发明。necessity of multilateral talks多边会谈的必要性