It's not safe to walk the streets at night.

夜间在街上走不安全。

《牛津词典》

It's not safe to swim alone in the river.

一个人在河里游泳不安全。

youdao

It's not safe enough for people to ride electric bicycles.

人们骑电动自行车不够安全。

youdao

It's a difficult problem that not everyone is smart -they vary in their ability -so we try to make a world in which it's pretty safe for the small investor who's not paying attention.

不是所有人都是聪明人,这是个难题,大家能力不同,所以我们试图营造一个环境,一个让小投资者感到安全的环境,而无需忧心忡忡

耶鲁公开课 - 金融市场课程节选

Because I'm going to assume, I'm gonna take it that it's important to you, that you not be tortured. So by seeing who you want to keep safe, this will help you see which one you think is you.

因为我想,找出你们觉得对你们而言重要的,人物，你们想保护的人物,这样就能帮助你们,找到自己所支持的理论。

耶鲁公开课 - 死亡课程节选

"After a while the pigeons realise it's not safe to be there, " he said.

BBC: Hawks to scare pigeons at Swindon library

But it's just not practical, it's not possible, it's not safe for them to do that.

BBC: Obesity rates fall in Philadelphia

"People will know it's not safe and move to another application, " said Al-Nafjan.

CNN: Saudi Arabia may block Skype, Viber, WhatsApp, others