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といえば， と言えば
1. speaking of ...
2. when it comes to ..., as for ..., if one were to say ...
tbd
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ない， 無い
1. nonexistent, not being (there)
2. unowned, not had, unpossessed
3. unique
4. not, impossible, won't happen
5. not
6. to not be, to have not
tbd
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
