A．people can't fall asleep
B．people may feel relaxed
C．people's blood pressure increases
D．people may find a more comfortable position
A．Resting frequently during the day．
B．Doing little exercise．
C．Sleeping late on weekends．
D．Having heart disease．
A．ease insomnia
B．help keep the body's natural rhythm
C．lead to worse insomnia later
D．have no effect at all
A．Classmates．
B．Colleagues．
C．Boss and secretary．
D．PR representative and client．