如图,线段AB是⊙O的直径,弦CD⊥AB,∠CAB=20°,则∠AOD等于____.
1964年的秋天,中国______,打破了超级大国的核垄断与核讹诈( )
如果一名选手的成绩是147分钟,请你依据样本数据中位数,推断他的成绩如何?
Shelly had prepared carefully for her biology examination so that she could be sure of passing it at her first ________.( )