—Can you see the map on the wall?—Yes,_________.

— Tom’s never done extra work for his class, _______he?—_______. He is the laziest boy in his class.

E-mail is very popular today. People hardly post letters, _________?

I can’t decide _____ .

 —President Obama has never been to Beijing, ______ he? — He visited the Great Wall on the afternoon of November 18th,2011.