Thanking and Appologizing

Boy : Here is your bag.

Girl : .......

Firman : Thank you for …..

Hilda : It’s nothing.

Tiara : Hey, you are stepping on my foot.

Donna : ………………….

Salma : May I borrow your pen, please?

Irma : Sure, you can.

Salma : ……………….., Irma.

Irma : Any time.

Ben : I’m sorry I didn’t do the homework. I really forgot.

Teacher: ………………

Sinta : Risa, this is a present for you. I hope you like it.

Risa : Oh, this is so wonderful ……………….

ALya : Can you help me with my English homework?

Desi : Of course.

Alya : Thanks a lot.

Desi : ……………

Do you understand today's material?

Which part of the materials is difficult? greeting, leave taking, thanking or appologizing?