上颌骨骨折最有意义的体征是（）
A.鼻孔大出血
B.牙的折断或错位
C.眼镜征
D.上颌骨出现动度并咬合错乱
E.牙龈撕裂
参考答案：D
若油气分离器在冬季启动，则应在启动前（）h通入蒸气或热水循环。
A、8
B、4
C、2
D、0.5
If a void occurs in the cargo hold, it is better to（）to control the broken stowage.
A.brace it with dunnage
B.cover it with large pieces
C.fill it with small pieces
D.leave it as it is
