dangerous的名词形式的反义词

例句：

The equation of wealth with happiness can be dangerous.

把财富与幸福等同起来可能是危险的。

Going into the projects alone is dangerous.

只身进入公房区是危险的'。

It's known as the most dangerous part of the city.

人们都认为那是市内最危险的地段。

I need hardly tell you that the work is dangerous.

这工作很危险，这就不用我说了。

It would be dangerous for you to stay here.

你待在这儿不安全。