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なんとなく， なにとなく， 何となく， 何と無く
1. somehow or other, for some reason or another, without knowing why
不知怎么的，不知为什么，不知为何
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わかる， 分かる， 解る， 判る， 分る
1. to understand, to comprehend, to grasp, to see, to get, to follow
2. to become clear, to be known, to be discovered, to be realized, to be realised, to be found out
3. I know!, I think so too!
明白，理解；清楚，明确、被了解、被发现、被认识、被实现；明白！我也这么想！
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
