He could hardly write his name at the age of 5, ________________?

--- She's never spoken to a foreigner, _______? --- Yes. She is active and can speak English freely.

— You like listening to Sally's songs, don't you?—_______.She has a sweet voice.

I don’t know how ________ commas. 

— There are still many old city walls in Xi’an, _______?—Yes, there are.