1.the expression to say thank or gratitude is .... 2.the expression to say sorry is .... 3.the expression to introduce your friend to someone is .... 4.the expr

Answer:
1. Thank you very much / I really appreciate that, thank you!
2. I'm sorry/ I'm really sorry
3. This is my friend ....(masukin namanya) / I'll intruduce my friend ....(masukin namanya)
4. I think i'll be leaving now / Good bye / bye
5. Hello there! / How are you? / How do you do?