评估培训与开发效果时，最重要的评估是( )。
A．反应评估B．学习评估C．投资收益评估D．结果评估
参考答案：D
Mike didn't ________ his parents and friends _ , he won the first in the competion. [ ]
A. let; down
B. make; happy
C. keep; clean
D. make; down
不分散低固相钻井液的特点是不分散和低固相。
