问题:
To be healthy, one must have at least _____ sleep every day.
A.eight hours
B.eight hour’s
C.eight-hour’s
D.eight hours’
To be healthy, one must have at least _____ sleep every day.
A.eight hours
B.eight hour’s
C.eight-hour’s
D.eight hours’
A.eight hours
B.eight hour’s
C.eight-hour’s
D.eight hours’
参考答案: