Where is your mother?— She has ______ to Sichuan on business. She has ______ there four times recently.
How helpful Susan is! —Yes. She neverto help others.
Could you please do some shopping for me, Mary?— Sorry, I ______ my homework.
_ Excuse me, _______is the nearest bookshop? _Go down the street and turn left at the second corner.
Is your father in?－ No, he ______ for three hours.