— Can you tell me the short _____ of London?—The best way to see London is by boat. After _____off the boat at Tower Bridge, you can have a walk around the Tower of London .
Please open a window _________ turning on air conditioning.
In those days ,books could only be produced one at a time _____________.
Food safety is important. Rules _____ to stop people from food pollution.
—Why don’t we start a school magazine on line? —________
The sign means _________