Because of the bad weather, my mother ____ and lay in bed. She ______ for a week. 

 Up to now, our society ________ with limited living space and a shortage of natural resources.

 My study of biology has ______ much of my spare time, but it has given me a great deal of enjoyment. 

—I remember you were a talented pianist at college.Can you play the piano for me?—Sorry，I ________ the piano for years.(2012·湖南)

 Tom ________ in the library every night over the last three months.(2011·北京)