非敞开式的甲乙类生产厂房应有良好通风,以减少厨房内部()的积聚,使之不至于达到爆炸范围。
A、有毒有害气体
B、可燃气体
C、可燃液体蒸气
D、可燃粉尘
参考答案:B, C, D
He is rather difficult to make friends with, but his friendship, ____, is more true than any other.
A.once gained
B.when to gain
C.after is gained
D.while gaining
颅脑外伤侧位平片显示鼻咽腔顶软组织肿胀常提示()。
A.前颅凹骨折
B.中颅凹骨折
C.后颅凹骨折
D.额骨骨折
E.斜坡骨折