Whenever I make mistakes, my mother will point them out with .
-----Could you tell me how long ________________? ------ About three days.
I don't know when he . When he , I'll let you know.
—I would like you to talk about the Great Wall. —I’m sorry, but ________ Jack ________ I have been there.
A report on history in our school next month.
Is this the factory __________ you visited the other day?