-Why does the river smell terrible?-Because large quantities of water______.
—When did Bob leave?—I have no idea. I ________ a shower upstairs.
She is a hardworking student, and all her spare time she has ________ staying in the library.
—Do you know the Water Cube at all?—No, this is the first time I ________ here.
A kind of newlymade shoes, if put into the market, ________ large orders because the heels can switch from 9 to 4 centimeters.
I had meant to meet you at the airport this morning but I was too busy for I ________ a report.