It is said in the book that Thomas Edison (1847—1931) ________ the world-leading inventor for sixty years. 

I first met your sister ten years ago, when she ____at a supermarket as a salesgirl. 

Susan decided not to work on the program at home because she didn’t want her parents to know what she ______. 

Although it _________ in the desert most of the year, people still live there.

The ambulance was just arriving, for a worker, who ______ the window on the second floor, fell off the window.