⑤how can we keep safe when we are are walking on

⑤how can we keep safe when we are are walking on the street为什么when放中间

这是一个时间状语从句，when是从句的标志词，必须放中间，才符合句意，表示当...的时候 。
本句意思：当我们在街上散步的时候，我们怎样才能保证安全呢？

大概是为了强调主句，把时间状语从句后置。

我们走在马路上时如何保证安全？

we should always be careful of those cars and bikes passing by if we want to keep ourself safe. first, make sure we are on the pavement, and take a look at your left and right all the time to make sure that there's no cars rushing to you. and second, don't run on the road, or you won't be able to stop in time if some troubles bump into you. if we follow these 2 tips, we should be safe.