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なければならない， なければなりません， なければいけない
1. have to do, must, should, ought to
必须，应该
に
1. at (place, time), in, on, during
2. to (direction, state), toward, into
3. for (purpose)
4. because of (reason), for, with
5. by, from
6. as (i.e. in the role of)
7. per, in, for, a (e.g. "once a month")
8. and, in addition to
9. if, although
tbd
の
1. indicates possessive
2. nominalizes verbs and adjectives
3. substitutes for "ga" in subordinate phrases
4. (at sentence-end, falling tone) indicates a confident conclusion
5. (at sentence-end) indicates emotional emphasis
6. (at sentence-end, risi...
句尾起强调作用；助词，表示所有关系
