The house is dirty because it ________ since they moved out.

I know little about the accident because not much ______ about it up to now.

 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. 

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