B. isn’t 原句应该是: it is lovely weather, isn't it?反义疑问句.主句用了肯定句,反义疑问句就要用:简短的,否定的一般疑问句.所以答案B是正确的
B主句省略了。(It is)lovely weather ,isn't it? 更具体的建议去看一下百度百科,绝对比我再解释要全。http://baike.baidu.com/view/1656124.htm ^_^
B. isn’t have a good day! :)