26. What is the probable cause of Krentz’s problem?

　　A) An unexpected gain in body weight.

　　B) Unexplained impairment of her nervous system.

　　C) Weakening of her eyesight with the setting in of winter.

　　D) Poor adjustment of her body clock to seasonal changes.

　　27. By saying that Linda Krentz saw the light” (Line 4, Para. 1), the author means that she ________.

　　A) learned how to lose weight

　　B) realized what her problem was

　　C) came to see the importance of light

　　D) became light-hearted and cheerful

　　28. What is the CURRENT view concerning the treatment of seasonal depression with bright lights?

　　A) Its effect remains to be seen.

　　B) It serves as a kind of placebo.

　　C) It proves to be an effective therapy.

　　D) It hardly produces any effects.

　　29. What is psychologist Michael Terman’s major concern?

　　A) Winter depressives will be addicted to using light boxes.

　　B) No mental patients would bother to consult psychiatrists.

　　C) Inferior light boxes will emit harmful ultraviolet lights.

　　D) Light therapy could be misused by certain mental patients.

　　30. Which of the following statements is TRUE?

　　A) Winter depressives prefer light therapy in spite of its inconvenience.

　　B) Light therapy increases the patient’s photosensitivity.

　　C) Eye damage is a side effect of light therapy.

　　D) Light boxes can be programmed to correspond to shifts in the body clock.

　　Unit 13

　　11.B 12.C 13.A 14.D 15.D 16.A 17.B 18.D 19.A 20.C

　　21.C 22.B 23.D 24.C 25.A 26.D 27.B 28.C 29.D 30.A