选择题：Heart disease is one of the() causes of death.

Her parents died when she was a baby and she was brought() by her aunt.

Human behavior. is mostly a product of learning ()the behavior. of animals mainly depends on instinct.

It is said that() boys in your school like playing football in their spare time, though others prefer basketball.

It was () of you to turn off the light while I was sleeping.

Our English teacher() our buying an English－Chinese dictionary.