题目

   下面是一则对话，请从所给的A—G选项中选择恰当的一项填入空格处，使对话的上下文意义完整，结构连贯；选项中有两项为多余选项。 WeChat, known as Weixin in china, is a mobile phone text and voice messaging communication service which is developed by Tencent.. In less than two years，WeChat has registered 200 million users ,   71    . Up to now WeChat is already one of most popular chat applications which are used in mobile phones. Undoubtedly, WeChat is definitely a wonderful invention that changed the world,    72     陆地气候相对干燥，陆地生活的动物一般都具有防止水分散失的结构．如昆虫具有（　　）A．外骨骼B．肺C．心脏D．触角