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必要， 必用， ひつよう
1. necessary, needed, essential, indispensable
2. necessity, need, requirement
必要的，必需的，必不可少的，不可缺少的；必要性，需要，要求
が
1. indicates the subject of a sentence
2. indicates possession
3. but, however, (and) yet, though, although, while
4. and
5. used after an introductory remark or explanation
6. regardless of ..., whether ... (or not), no matter ...
7. indicates a des...
tbd
