—___these her erasers?
—No, they ___.
A:Is, isn't
B:Are, aren't
C:Are, is
D:Is, are
下列内容中,属于唐太宗的政治主张的是( )①皇帝要勤于政事 ②皇帝要居安思危 ③大臣要廉洁奉公 ④政府要轻徭薄赋
当x____时,1-2x是二次根式.