单项选择题
A．What would life be like without memory B．Memory is of vital importance to life. C．How is a person’ s memory different from an animal’ s or a computer’s D．What is contained in memory
A．the unnoticed motion of his muscles B．"participating" in the performance C．bending an ear to the music D．being the conductor of the orchestra
A．Because they are easy to steal. B．Because they are difficult for people to obtain. C．Because they are not easy to carry around. D．Because they themselves are expensive, too.