肥煤单独炼焦时主要产生（）裂纹，产生的焦炭易碎成小块，耐磨性差。
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平行吊装绑扎法若用一个吊点，它只适用于短小、重量轻的物品。
A. 正确
B. 错误
Which of the listed precautions should be taken when cleaning the internals of a motor with compressed air?（）
A. Open the machine on both ends so as to allow the air and dust to escape
Be certain that the circuit breaker is opened and tagged on the feeder panel
C. Be certain that the air is clean and as dry as possible
D. All of the above
风载荷会对物体产生受力的变化。
A. 正确
B. 错误
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