This is the 5302nd most frequent Chinese word.
为什么不
"Why not?"
The phrase '为什么不' (wèishénme bù) is used here to express a suggestion, indicating curiosity or encouragement for someone to try doing something they might not have considered.
你为什么不试试参加这个比赛？
Why don't you try participating in this competition?
Here, '为什么不' is part of an explanatory statement, questioning the reason behind an action that was not taken.
我不明白为什么你不告诉我这件事。
I don't understand why you didn't tell me about this matter.
In this sentence, '为什么不' is used to suggest an activity in a rhetorical manner, implying the recommendation as a natural choice.