A．Advancement in neurophysiological measurement.
B．Improvement in experimental psychology.
C．Studies of the electrical potentials of the brain.
D．Experiments of physiological changes in the body.

A．sarcastic
B．poignant
C．laudatory
D．critical

A．different people may have quite different sleep requirements
B．we can leave our bodies to regulate our sleep requirement for itself
C．we can maintain normal behavior and working standards no matter how mueh we have slept
D．we may remain efficient even if we have one night's loss of sleep

A．For both of theme only fatigue can promote sleep.
B．For both of them, overeating may promote sleep.
C．For both of them, they wake only to satisfy their bodily needs.
D．For both of them, they need to be completely satisfied to promote sleep.

A．insufficient sleep may become dangerous to our civilization
B．excess of sleep may cause a loss to the community
C．we do not need as much sleep as we take
D．deprivation of sleep in emergencies may do no harm to our body