—_______ does Mary surf the Internet? — Every day. A. How long B. How many C. How often
We have only one Earth. It’s our common _.
—Need I wash your car after repairing it? —Yes, that would be much _.
—When will he leave for Shanghai? —As soon as he _ his work.
Tom’s mother is busy _____ breakfast for Tom.
—Could I use your eraser for a while? —Yes, of course you _.