12. The advice of American doctors is all about
B) complex measures that ensure healthy sleep.
13. Americans are referred to as a “somnambulant nation” because they
D) don’t get enough sleep to function effectively.
14. Experiments with sleep deprivation proved that
C) it is likely to result in cardio or nervous problems.
15. There is a tendency to sleep less because
B) people think they can reduce sleeping hours without any harm.
16. Having naps during the day would be nice, but
C) bosses are against this.
17. People who work at night can hardly
B) consult doctors when needed.
18. The main aim of specially designed shift-work lighting system is
A) to help people feel alert at night.