I only want a snack. I'm not very hungry.
我只想要一份快餐。我不太饿。
A Sorry to be late, everyone.
A 对不起大家，我来晚了。
B Hi, don’t worry - take a seat. What can I get you?
B 你好，不必在意——坐下。你想要什么？
A I only want a snack. I'm not very hungry.
A 我只想要一份快餐。我不太饿。
B That's not like you!
B 这可不像你！
A No, but I had dinner with the family. It's my sister's birthday today.
A 是的，但是我已经和家人吃过饭了。今天是我姐姐的生日。
B Well, help yourself. There's plenty of food left.
B 哦，那你随便。还剩下足够多的食物。

Notes注释
1 If you go to dinner with friends, and you have reason for not wanting to eat very much, you can explain: I only want a snack. / I only want a snack. / I'm not very hungry. / I'm not very hungry. / I had dinner with the family. / I had dinner with the family.
如果你去和朋友吃饭，而且你有理由不想吃得太多，你可以这样解释：I only want a snack. /我只想要一份快餐。/ I'm not very hungry. /我不太饿。/ I had dinner with the family. /我已经和家人吃过饭了。
2 If you are surprised at a friend's behaviour, you can say: That's not like you! / That's not like you!
如果你对朋友的举止很吃惊，你可以说：That's not like you! /这可不像你！

Key phrases and sentences
Sorry to be late, everyone.
Hi, don’t worry - take a seat.
What can I get you?
I only want a snack.
I'm not very hungry.
That's not like you!
No, but I had dinner with the family.
It's my sister's birthday today.
Well, help yourself.
There's plenty of food left.

对不起大家，我来晚了。
你好，不必在意——坐下。
你想要什么？
我只想要一份快餐。我不太饿。
这可不像你！
是的，但是我已经和家人吃过饭了。
今天是我姐姐的生日。
哦，那你随便。
还剩下足够多的食物。