【单选题】下面哪种调查方式的样本不是随机选取的( )
D.
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【多选题】古罗马共和国后期出现了“前三头同盟”,事实上瓦解了共和国的基础。这三人是( )。
【简答题】A.He was not hungry. B.He had already had his breakfast. C.He was too tired. D.He wanted to sleep a little more.
【简答题】By the time he was ten,Edison______experiments in chemistry. A.had already done B.already had done C.was already doing D.already did