有later,句子用什么时态?

Go get you lunch first and you can finish this later.
Let's go to lunch now,we'll come back and finish this later.
He called and told me that he will be back later.
Sooner or later he will find his way here.
这些都是100%语法正确的句子,句中都有 later,也都以各种不同的时态写成.
时态与 later 这个单词无关.