多索茶碱作用时间长，其作用是茶碱的（） A.2～5倍 B.5～10倍 C.10～15

Directions: Read the following text and choose the most suitable heading from A – F for each paragraph. There is one extra heading which you do not need.

A．Major findings of the study B．Stress matters． C．Interpersonal relationships and stress． D．The sense of humor and stress． E．Choosing subjects to study． F．Other characteristics typical of super．young people

How They Stay Young
76.________________
When Dr David Weeks，a clinical neuro-psychologist at the Royal Edinburgh Hospital in Scotland．wanted to look into the secrets of eternal（永久的） youth ，he advertised for subjects who looked younger than their age．An independent panel examined photographs of respondents，and selected 3,500 people who looked on average l2 to 14 years younger than their actual age to take part in the study．
77．________________
These subjects were studied for eight years．The main aim of the study was to discover whether environment or heredity had more effect on the ageing process．The conclusion was that genetic programming is the main factor．But the study also showed that avoiding stress can slow down the ageing process．
78．________________
Stress seems to have an immediate effect on appearance．A separate study of middle-aged women showed that women suffering form serious stress looked older in just a few months．Yet when the problem causing the stress was removed，they very quickly looked younger．
79．________________
Here is a list of the factors that Dr．Weeks found that allowed his subjects to lead less stressful lives than others．First，they tend to have happy relationships with their partners．These relationships are based on trust and empathy，and provide security and comfort when dealing with stressful problems．Secondly，they tended to avoid sources of hostility instead of allowing them to make them angry．
80．________________
Next, they seem to have a good sense of humor．They like to have fun，and are enthusiastically involved in a variety of hobbies．They also seemed less willing to conform to others’ ideas．They prefer to think for themselves．They tend to have a good attitude towards health and exercise as well．They avoid the sun，do not smoke, and eat a healthy diet．
So these are the secrets of the “ super-young”：a loving relationship．Regular exercise．a variety of hobbies，a healthy diet and avoidance of stress．