She kept her past secret from us all.

她对我们所有人都避而不谈她的过去。

《牛津词典》

The top-level international research team, who have studied her in secret for the past two years, believe she is the most complete and best preserved primate fossil ever uncovered.

过去的两年里，一支最高水准的国际研究队伍一直对她进行秘密研究，他们相信她是迄今为止所发现的最完整，保存得最完美的灵长类化石。

youdao

Nearly everybody has a creek in his or her past, a secret waterway where one spent the spring of one's youth.

几乎每一个人的过去都流淌着一条小溪，它发源于少年时代，一路潺潺絮语而来。

youdao

While she keeps her past a closely guarded secret, even from her employer, she remains true to her activist roots: she regularly writes for magazines critical of Beijing and joins pro-democracy demonstrations.

CNN: Halfway House No More

Seattle's Visqueen has long felt like a closely guarded regional secret, in part because singer Rachel Flotard spent the past few years caring for her terminally ill father.

NPR: Visqueen: A Ferocious Song Of Devotion