【单选题】听力原文: More than sixty percent of all homes in the United States have at least one thing in common: the people living in them keep one or more small animals as pets. These pet owners spend about ten bi...
A.
They keep one or more small animals at home as pets.
B.
They kill animals from time to time.
C.
They let animals run or fly away now and then.
D.
They exchange their animals year in and year out.