A conscious victim who has suffered a blow
题型：单项选择题
问题：
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（）.
A.turning the victim's head to the side to keep his airway open
B.positioning the victim so the head is lower than the body
C.giving the victim water if he is thirsty，but no food
D.elevating the head and shoulders slightly with a pillow
0竖直向上抛出，已知箱子所受空气阻力与箱子运动的速率成正比，且运动过程中始终保持图示姿态。则下列说法正确的是