seen是什么时态

　　I can't see any future in this relationship.

　　我看不出这个关系会有什么前途。

　　Down through the years this town has seen many changes.

　　这些年来这座城市发生了许多变化。

　　Now let me see ─ how old is she now?

　　让我想一想，她现在多大了呢？

　　I'll see what I can do to help.

　　我考虑考虑，看我能帮上什么忙。

　　Bring it into the light so I can see it.

　　把它拿到亮的地方，好让我看见。