GRE argument 105题目：
The following appeared in a health newsletter.
"According to a recent study, people with many social ties report catching colds(4) less often than do people with few social ties(1,2,3). Consequently, researchers conclude that having an active social life(5) probably helps strengthen the immune system(6). The researchers note that catching a cold—one of a family of highly contagious viruses—gives the cold-sufferer temporary immunity(6) to that virus in the future, but not to the many other related viruses. Merely being exposed to a new cold virus, however, is not enough for a person to catch a cold, since a strong immune system can successfully fight off some new viruses. Thus, in order to prevent catching a cold, people should strengthen their immune systems by becoming more active socially(7,8)."
(1)The author fails to establish a causal relationship between having many social ties and lower frequency of catching cold.
(2)The author fails to rule out the possibility that some people avoid social activities just because they are more likely to catch colds.
(3)There may be other differences between people who have many social ties and those who do not.
(4)Different groups of people may have different definition of catching colds.
(5)The researchers simply equate having many social ties with taking an active social life.
(6)No evidence could indicate that exposure to virus could strengthen the immune system, and how long could the temporary immunity be effective.
(7)Merely becoming more socially active may not strengthen people’s immune system sufficiently.
(8)The author fails to consider negative effects for some people to have an active social life.
无论是GRE issue还是GRE argument，考生都应该养成写提纲的习惯。这种提纲式的GRE写作练习可以帮助考生锻炼写作的逻辑性，而GRE写作高分最重要的得分依据就是作文的逻辑性要强。