•We all arrived safely.我们都安全到达。

•Drive safely (= Do not take any risks) !谨慎驾驶！

•Are the children safely fastened into their car seats?车里的孩子们都系好安全带了吗？

•I think we can safely (= with no risk of being wrong) say they won't find us now.我觉得我们可以有把握地说，他们现在找不到我们。