()
A. By asking people to report their sleep habits.
By observing people's sleep patterns in labs.
C. By having people wear motion-detecting watches.
D. By videotaping people's daily sleeping processes.
()
A. It has made remarkable progress in the past few decades.
B. It has not yet explored the cross-cultural aspect of sleep.
C. It has not yet produced anything conclusive.
D. It has attracted attention all over the world.
()
A. Her unique personality.
B. Her physical condition.
C. Her shift of interest to performing arts.
D. Her family's suspension of financial aid.
()
A. She was not an outgoing person.
B. She was modest and hardworking.
C. She was easy-going on the whole.
D. She was usually not very optimistic.
()
A. She was influenced by the roles she played in the films.
B. Her parents taught her to sympathize with the needy.
C. She learned to volunteer when she was a child.
D. Her family benefited from other people's help.
微信支付 
支付宝支付