sở dĩ means "the reason why" (conjunction). the reason why.
How is sở dĩ pronounced?
You can listen to sở dĩ on this page in both Northern and Southern Vietnamese accents.
How is sở dĩ used in a sentence?
For example: Sở dĩ tôi đến muộn là vì tắc đường. (The reason why I was late is because of traffic.); Sở dĩ anh ấy thành công là do chăm chỉ. (The reason why he succeeded is because he worked hard.).
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