unperceived

He slipped out of the room unperceived by anyone.

用法提示：unperceived 是形容词，作主语补足语，表示“未被察觉的”。

The change was so subtle that it went unperceived for weeks.

用法提示：unperceived 作表语，与 went 构成系表结构，表示“未被感知的”。

Many small signs of illness go unperceived until they become serious.

用法提示：unperceived 作表语，说明主语处于“未被察觉”的状态。