To protect Chinese retailers against the growing foreign competition, the Chinese government still takes measures to limit the numbers of stores opened by foreign retailers in large cities.

A．sleep for at least eight hours per night
B．believe that we need less sleep as we age
C．adjust our activities to new environment
D．be able to predict the rhythms of our biological clocks

A．Most people need less sleep when grown older.
B．Most people need seven and a half hours of sleep every night.
C．On average, people in the US today sleep less per night than they used to.
D．Most people need more sleep when they are under pressure.