C．so many participants would take singing classes

　　D．participants in the singing classes would bond so quickly

　　解析：选D　推理判断题。根据第四段的最后两句可知，这些研究人员没有料到很多人在一起唱歌时会那么快地建立友谊。

　　3．Paragraph 5 shows that reasons for the results of the research are ________.

　　A．very cheering

　　B．very interesting

　　C．a bit confusing

　　D．not completely possible

　　解析：选D　细节理解题。根据第五段的内容可知，提到的那两点都只是有可能是那些结果的原因，但并不是很确定的，故选D项。

　　4．According to Eiluned Pearce, really close relationships ________.

　　A．are easy to develop

　　B．depend on one's attitude

　　C．often occur in large groups

　　D．rely on individual communication

　　解析：选D　细节理解题。根据Eiluned Pearce在末段说的"Really close relationships still depend on communication between individuals or much smaller groups"可知，答案应选D项。

　　B

　　More than four in 10 cancers - 600,000 in the UK alone - could be prevented if people led healthier lives, say experts.

　　Latest figures from Cancer Research UK show smoking is the biggest avoidable risk factor, followed by unhealthy diets.The charity is urging people to consider their health when making New Year resolutions (决心)．Limiting alcohol intake and doing regular exercise are also good advice.

　　According to the figures from 2007 to 2011, more than 300,000 cases of cancer recorded were linked to smoking.A further 145,000 were linked to unhealthy diets containing too much processed food.Obesity (肥胖) contributed to 88,000 cases and alcohol to 62,200.Sun damage to the skin and physical inactivity were also contributing factors.

Professor Max Parkin, a Cancer Research UK statistician based at Queen Mary University of London, said，"There's now little doubt that certain lifestyle choices can have a big impact on cancer risk, with research around the world all pointing to the same key risk factors."