Do you have a pen?
请问你有笔吗?
Could you lend me a pen?
可以借支笔吗?
Yes, of course.
是的, 当然有。
Here you go.
当然, 拿去吧。
I wonder if you could do me a favor?
不知可否帮个忙吗?
Sure, there you go.
当然, 拿去吧。
Sure, here you are.
当然, 拿去吧。
I don't have one with me.
我没有。
I don't have any actually.
事实上我没有。
I owe you one.
我欠你一份情。