今后你要更加小心。 这句话翻译成英文

You should be more careful next time.

You must be more careful from now on.

from now on: 今后，从现在起。

later on, next time， in the future 都没有表示从现在起。

in future 不对, 应是 in the future

您好 根据您的提问 以下是我的回答：
You have to be more careful in future.

You must be more careful in future.（in future就是今后的意思）