A : Hey Edo!
B : Hey,what's up?
A : are you understand of what Mrs.Ina says?
B : No, i don't understand. Can you tell me for clearly?
A : Yes,sure. You must do your homework. Because,tomorrow we should submit it~ Do yo understand what i mean?
B : Yes of course. Thankyou Doni! :)
A : Your welcome
Check someone's understanding:
A: Do You understand of what seĀ  said?
B: Yes, she said that we should speak english in our english class.

A: Do you know i mean?
B: yes, sir

A: Do you understand the text?
B: i'm trying mam

A: Do you understand what the teacher ask to do?
B: We should use english in our english class.

Ask someone's attention:
A: Attention please, Attention!
B: yes, mam

A: Excuse me, mam . may i wash my hands?
B: yes, sure

A: Hey, let's go to the canteen
B: sure, let's go

A: Everybody, are you ready to learn English today?
B: yes,mam