SGZ系列钻机组装机时立轴合不上的原因是什么？
参考答案：
把立轴向上方托平抬起，清查齿轮与合箱夹盘内有无脏物。
素质教育以提高__________为根本宗旨。
The reason ____he was late was ____he had taken a wrong bus.
A．why; because
B．for; because of
C．why; that
D．for; that
