leave signal

例句：

1. 1.The car left a trail of dust behind it.
   汽车留下了一串尘土。
2. 2. She sent a message by leaving a note on her desk.
   她通过在办公桌上留下便条来发送信息。
3. 3. The plane was instructed to leave the airport early to avoid delays.
   飞机被指示提前离开机场以避免延误。