确定底孔直径的大小，要根据工件的()、螺纹直径的大小来考虑。
A、大小
B、螺纹深度
C、重量
D、材料性质
参考答案：D
23. The class is unusual_______ the students are all over fifty and none of them attended the middle school when they were young.
A．in how
B．in what
C．in which
D．in that
“不愤不启，不排不发”教育思想最早出自（）
