1. [单选题]The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by_______.
A. large conical springs
B. compressed air pressure
C. hydraulic pressure
D. exhaust gas pressure
2. [单选题]水泡型烧伤，根据烧伤分类是()。
A. Ⅰ度
B. Ⅱ度
C. Ⅲ度
3. [单选题]Which of the following conditions is true concerning a flammable liquid with a concentration above the upper explosive limit?
A. The mixture is too lean to burn
B. The mixture is too rich to burn
C. The vapor is about to explode
D. Conditions are perfect for combustion
4. [单选题]鼻骨骨折常引起如下改变______。
A. 外鼻肿胀和畸形
B. 鼻出血、鼻部和眼睑部瘀斑
C. 鼻触诊有捻发音
D. 以上都是
5. [单选题]颈椎损伤的伤员，转院时，______搬动头部。
A. 可随意强行
B. 为缓解头痛可以
C. 可两人一起
D. 严禁随意强行
