It doesn't matter._____ careful next time.

It doesn't matter._____ careful next time.
It doesn't matter._____ careful next time.

It doesn't matter._____ careful next time.
be

Be

Be
be careful 当心，小心

Be

答案Be。
careful是形容词，前面用be动词修饰，完整的可以说成You can be careful next time.