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飛行時間， ひこうじかん

1. flight time, number of flight hours

tbd

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どのくらい， どのぐらい， どの位

1. how long, how far, how much

多少，多远，多长

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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

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