增大加热炉热负荷要防止（）。
A、炉膛形成正压
B、闷炉
C、燃烧器火焰脱火
D、加热炉超负荷
参考答案：B
—Does Antonia always finish his homework on time?
—Yes, of course. He ______ leaves today's work for tomorrow. [ ]
A. also
B. hardly
C. only
D. usually
通常导致采煤机电动机温度升高过负荷的原因是（）和（）。
