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努力， どりょく
1. effort, exertion, endeavour, endeavor, hard work, striving
努力
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必ず， かならず
1. always, without exception, necessarily, certainly, without fail, positively, invariably
必须，必定
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题；表示与另一选项（无论是否明确提及）形成对比；表示强调
