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忘れる， わすれる
1. to forget, to leave carelessly, to be forgetful of, to forget about, to forget (an article)
忘记；随意丢弃；疏忽；忽略；不再提及(某事)；遗忘了(某物品)
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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
