Backchannel
（传递消息的）秘密渠道, 特殊途径
🗣️ 情景例句
I need to post a letter.
我得去寄封信。
I know the boy whose father is a writer.
我知道那个男孩的父亲是作家。
I'm afraid that Jim will miss a lot of his lessons.
恐怕这么一来，吉姆要缺很多课了。