She felt sure the letter had some hidden meaning.

　　她確信那封信中有言外之意。

　　There are fears of a hidden agenda behind this new proposal.

　　人們擔心這一新提議的背后有不可告人的目的。

　　I stayed hidden; I couldn't chance coming out.

　　我躲了起來(lái)，不能冒險出去。

　　He knew the hidden drifts in that part of the river.

　　他對那段河道中的暗流非常清楚。

　　I keep my private papers hidden.

　　我藏起了我的私人文件。