单选题
There is no doubt that smart homes not only make life much more comfortable and convenient but they are also energy efficient.
【正确答案】
B
【答案解析】本题的关键在于找准句子的主干。本句主干是There is no doubt…,译为“……是毫无疑问的”。that引导同位语从句,说明doubt的具体的内容。从句的主语为smart homes,从句中用not only…but…连接两个并列结构,译为“不仅……而且……”。