颌骨骨髓炎X线呈"虫蚀状"低密度区的病理基础是（）
A. 骨膜增生，骨膜加厚
B. 骨组织增生，骨小梁增粗
C. 骨组织吸收，骨小梁结构不清
D. 死骨形成，肉芽组织充填
E. 新骨形成，骨小梁不规则
稀油站油温工作范围是（）℃。
A. 5-25
B. 15-35
C. 25-45
D. 35-55
A vessel is proceeding from a very cold climate to a warm climate.With a cargo of non-hygroscopic nature，which of the following is correct?（）.
A. There is danger of heavy cargo sweat if outside air is introduced by ventilation
B. Danger of the ship sweat exists.Constant and vigorous ventilation is required
C. There is little danger of ship's sweat;slight possibility of cargo sweat
D. The possibility of any ship or cargo sweat is remote
对接接头进行强度计算时，（）接头上的应力集中。
A. 应该考虑
B. 载荷大时要考虑
C. 不予考虑
D. 精确计算时要考虑
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