题目

据报道1994年12月科学家发现了一种新元素，其原子的原子核内有161个中子，质量数是272，该元素原子的质子数为    A．272          B．161         C．111             D．433 答案：  C —I went to work on foot yesterday, though it _________ cats and dogs. —You __________ by bus. It was likely to get a cold. A. is raining; must have gone                     B. rained; would go C. was mining; should have gone         D. have rained; could have gone