I don't understand a sentense.Please help me!Thanks!
"In retrospect,it became clear to me that this incident was indeed key——and key in more than one sense."Can you tell me what meaning it is?And what's the function of the "dush"?Answer me in Chinese or English , both ok.Thanks!

Question

Answer

As the character thought about the event or incident in the book referred to, he or she saw it as an event of major importance.  Of major importance in more than one way.  The dash serves to set apart and emphasize that sentence fragment which explains the word "key" in the main sentence.

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