他决定对这个秘密守口如瓶，再也不提。

He decided to ___keep the secret ___to ___himself and never spoke of it again.

她将自己的疑虑藏在心里，只向日记本倾诉。

She ___kept her doubts ___to ___herself, confiding only in her diary.

如果你有内部消息，明智的做法是不要告诉别人，以避免任何利益冲突。

If you have insider information, it's wise to ___keep it ___to ___yourself to avoid any conflict of interest.