正方体ABCD-A1B1C1D1中,AB的中点为M,DD1的中点为N,则异面直线B1M与CN所成的角是[ ]
A.0°
B.45°
C.60°
D.90°
答案:D
患者,男性,75岁。因突发神志不清5小时入院。查头颅CT示脑干出血,在急诊发现患者呼吸不规则,气管插管后收住ICU予机械通气,测血压150/60mmHg。建议患者的体位为()
A.平卧位
B.侧卧位
C.头低脚高位
D.头高脚低位
E.30°~45°半卧位
She has an extraordinary command of the English language.[ ]
A. earned
B. won
C. derived
D. acquired