When people engage in activities that help others, their brain releases endorphins, the brain’s natural opiates, which induce in people a feeling of well-being. It has been suggested that regular release of endorphins increases people’s longevity. And a statistic on adults who regularly engage in volunteer work helping others shows that they live longer, on average, than adults who do not volunteer. However, that statistic would be what we would expect even if volunteering does not boost longevity, because___________ Which of the following most logically completes the argument? A In the communities studied, women were much more likely to do regular volunteer work than men were, and women tend to live longer than men do B The number of young adults who do regular volunteer work is on the increase C The feelings of well-being induced by endorphins can, at least for a time, mask the symptoms of various conditions and diseases, provided the symptoms are mild D It is rare for a person to keep up a regular schedule of volunteer work throughout his or her life E Some people find that keeping a commitment to do regular volunteer work becomes a source of stress in their lives 错选了C，答案给的A。A说女士比男士更可能做志愿活动，女士比男士活得长。这不是支持原文了么？可以题目不是应该驳斥吗？

求may老师解答

求may老师解答

老师你好，数学课本第29页例4题，我没看懂解答1和2中的组合问题。谢谢！

这一题没看懂是怎么解M和N的，为什么等于84？不是改86吗？

老师没听懂，哪里来的2呢

2的三次方 5的三次方是什么呀？

np 2*2是什么意思 不懂为什么选E

老师你好 这道题的n怎么选数字来解它 那么多数字 为什么偏要选择0 1 2…？

老师你好，左边这道题解法听明白了，但是3k加2乘以15k加3这个方程不会解，最近看好多题都是不知道怎么解方程，我全忘了。数学书我看了，有概念，但是没教怎么解方程的！请先告诉我这道题那个地方是怎么回事，再教我怎么做，谢谢！