(一).Help yourself.

尽情吃 随便用。
May I start eating breakfast?
我可以吃早饭了吗？
Help yourself. I have many kinds of food for you.
快吃吧，我给你准备了好多吃的。

(二).I am stuffed.

我吃饱了。
How would you like some ice cream?
你要再吃点儿冰激凌吗？
No, thank you. I am stuffed from the dinner.
不，谢谢。我晚饭吃得很饱。