Definition
to disclose confidential information to someone or permit them to participate in something exclusive.
告訴某人秘密；允許參與
She decided to let John in on the preparations for the surprise party.
她決定讓約翰參與驚喜派對的籌備。
In the meeting, the manager let the team in on the company’s new plan.
在會議中，經理讓團隊知道公司的新計劃。
It took him a long time to let me in on the secret.
他花了很長時間才讓我知道這個秘密。