总体的定义是指根据研究目的确定的
A.所有样本的全体
B.观察单位的全体
C.同质观察单位的全体
D.观察单位某种变量值的集合
E.所有样本中同质观察单位某种变量值的集合
参考答案:C
—You could always put the decision off a little bit longer.
—________ If I leave it much longer I might miss my chance.[ ]
A. That's reasonable advice.
B. Isn't it a good idea?
C. Do you think so?
D. I can't agree more.
热机的分类:最早的热机是______;其次是______;______;______.