Once the sands have run out of a person's hourglass, they cannot be replaced.

Once the sands have run out of a person's hourglass, they cannot be replaced.

A.If a person s clock goes wrong, nobody can repair it.

B.Once an hour is gone, it will never come back to us.

C.Time is as precious as sands in an hourglass.

D.Sands can easily run out of an hourglass.

正确答案是B