【单选题】

Researchers know there are many drugs that can alter our bodily processes in such a way (67) affect our emotional experiences. One such set of drugs is commonly (68) as sedatives or tranquilizers. They act to "slow us down" (69) and make us less responsive.A、doctor may (70) a tranquilizer for someone who is very tense or very (71) and who cannot sleep or function because of his over-arousal (过于兴奋).Emotional disorders of extreme over-arousal are often (72) reduced by such drugs.

(73) set of drugs is called stimulants. They "perk us up" emotionally and make us (74) responsive.A、common mild stimulant is caffeine, a drug (75) in most coffees. It is because of its caffeine content (76) coffee often gives us a "lift" , wakes us (77) and helps us be more responsive. Some (78) are very potent and may effectively counteract extreme depression. (79) a doctor’s care, the use of strong stimulants can be very (80) .
Other (81) of drugs can also have profound (82) on our emotions. These include chemicals found in marijuana, narcotics, and hallucinogenic (引起幻觉的) (83) such as LSD、These drugs may produce unpleasant (84) pleasant feelings.Also they can be very dangerous. Some are strongly (85) , and many can cause various kinds of (86) .
A、set B、sort
C、kindD、kinds