地质工作者在不同的地层内发掘到许多化石.甲层中发掘出恐龙蛋、始祖鸟、龟化石;乙层中发掘出马、象牙、犀牛等化石;丙层中发掘出三叶虫、珊瑚、乌贼等化石.据此推断这些地层的年代由远到近的顺序是( ) A.甲、乙、丙 B.乙、甲、丙 C.丙、乙、甲 D.丙、甲、乙 答案:D-- Must we go there together? --______ you ________ he goes there, only one student is neededA.Both; andB.Either; orC.Neither; nor