【简答题】分层抽样的优点是|单纯随机抽样的优点是|整群抽样的优点是|系统抽样的优点是A. 简单、直观、标准误易计算B. 按比例分配样本,简便易行C. 便于组织,节约经费,易于控制调查质量D. 对各层可采用不同的抽样方法,抽样误差小E. 对所有观察对象进行调查,全面完整
【单选题】It was in this garden of his old house ______ he grew up ______ he dug out a pot of gold. [ ]
【单选题】It was in the garden of the old house _____ he bought last year ______he dug up a pot of gold.
【单选题】The farmer was horrified at the ______ that he has dug from under the field.
【单选题】It was in the garden of his old house _______ he grew up that he dug up a pot of gold.
【简答题】《左传·昭公三十二年》“三后之姓,于今为庶,王所知也”中“姓”意思是()。