单选题 《复合题被拆开情况》 Each of us is working hard to be happy. Happiness brings substantial benefits for society【C1】______. There is clear and【C2】______evidence that happier people have better overall health and live longer than their less happy peers. They can reduce their【C3】______to a cold or a heart attack by【C4】______50%. Happier people are more likely to wear seat belts and【C5】______road accidents. Happier people are even more financially responsible, tending to【C6】______more rigorous control over their expenditures. Most importantly of all, people who are happier are more【C7】______to make positive contributions to society and participate in public activities. They also have a greater respect【C8】______law and order and offer more help. There is even evidence that happiness is contagious or spreading,【C9】______happier people help others around them to become happier too. In other words, how happy we are has a measurable impact on the【C10】______of our friend’s friends.《问题》：【C4】