下列山脉中,既位于第二、第三阶梯分界线上,又是省级行政区大致界线的是( ) A.昆仑山 B.武夷山 C.太行山 D.南岭 答案:C14.-Will you go to the suburb for the holiday?-No.I'm fully occupied,for there are so many problems ________.( )A.remaining to settleB.remained settlingC.remaining to be settledD.remained to be settled