This book cost her twenty yuan ,        ?

 —He's never late for school, _________? —_____, never. He always gets to school on time.

— You come from England, don’t you?—       . How do you know that?

Yoga (瑜伽) helps people to keep healthy and relaxed, _______?

-- Peter didn’t use to be heavy, did he?-- ________. But look, how thin he is!