一______are you staying in Tibet?—Just for four days.
—Mom, where is my schoolbag? —______. Is it under the bed?
—____________? —They're fine, thank you.
—Is this your bicycle, David? —No, it's not . It's Helen's.
— Your English is very good. —____________ .
— ________, where is my pencil? — ________, I don’t know.