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無駄にする， むだにする

1. to render futile, to bring to naught, to waste, to not make good use of

tbd

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時間， じかん

1. time 2. hour 3. period, class, lesson

时间的单位：小时；小时；时间，时刻

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を

1. indicates direct object of action 2. indicates subject of causative expression 3. indicates an area traversed 4. indicates time (period) over which action takes place 5. indicates point of departure or separation of action 6. indicates object of d...

表示动作的直接对象；表示经过的场所；表示离开或分开的点

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取り返す， 取返す， とりかえす

1. to get back, to regain, to recover, to make up (for), to catch up on

tbd

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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

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