• A. fall asleep again.
• B. become more energetic the following day
• C. sleep less than 7 hours
• D. confirm those serious consequences
• E. suffer sleep problems
• F. sleep more than 8 hours

One survey showed that people who habitually ______ each night have a higher risk of dying.

A．with the development of indexing art.
B．with the development of artificial intelligence.
C．by taking up more tasks and experiments.
D．by establishing more computer libraries.

A．painful
B．painless
C．enjoyable
D．marvelous