单选题 The weight of the moon is only about ______ of that of the earth.
A. one eighty B. one of eighty
C. one the eightieth D. one eightieth

【正确答案】 D
【答案解析】[解析] 考查分数的读法。先用基数词读分子，再用序数词读分母，二者间不需冠词。