【og16新增】一道题，想不通啊，求大神们解答

lvlv10 发表于 2015-12-17 12:24
124.        
【Stimulus分析】     CP:  It  is  widely  assumed  that  people  need  to  engage  in   ...

alzn2765 发表于 2015-9-26 16:37
充分必要条件找削弱
simply talking to other people suffices to maintain mental sharpness as they age ...