With his mother she was stiff and on her guard.

与他的母亲，她僵硬，她的防范。

youdao

There was something about him which ought to put her on her guard .

他身上有一种气息，她应当时刻提防。

youdao

Next morning, before the Dwarfs left for the mine , they warned Snow White to be on her guard .

第二天早晨，小矮人们要去矿山工作了。他们告诉白雪公主好好看好门户。

youdao

She was wary, trained to expect little of life, grateful for small pleasures, on her guard against promises, accustomed to making the best of things, in the habit of both wanting and not daring to want something more.

NEWYORKER: Miracle Polish

So you had attacks coming on Iraq, on her vote on Iran on the Revolutionary Guard being designated as terrorists, and on Social Security.

NPR: Dems Vying for President Wary of Attacking Clinton

Knox recounts in her diary early on that a male prison guard winked at her when she got letters from men, often brought up her sexuality and gave her the impression he was making a pass at her.

BBC: Amanda Knox and prison life