单项选择题 A continuous watertight bulkhead on a ship is normally also a(n)（）.

单项选择题 A continual worsening of the list or trim of any floating ship indicates（）.

单项选择题 A conscious victim who has suffered a blow to the head has symptoms that indicate the possibility of concussion. If the patient feels no indication of neck or spine injury，recommended treatment would include（）.