明朝的北京城是典型的大一统王朝的都城,它有三重,请问皇帝住在里面的哪一重( )
蝴蝶和家蚕的发育过程一样,要经历四个时期,它们的发育顺序是( )
Peter's teacher is so proud that he is the only one of the brightest students ________ his degree.
若a<b,则下列各式中不成立的是( )