腰椎穿刺术后须去枕平卧4～6小时，其目的是防止（）
A.穿刺部位出血
B.低压性头痛
C.穿刺部位感染
D.颅内感染
E.脑脊液外漏
参考答案：B
A nine-year-old kid, waving ________, drove his family’s cows home
A．a stick of his half height
B．a half his height stick
C．a stick his half height
D．a stick half his height
生石灰加水水化后可立即用于配制砌筑砂浆用于砌墙。（）
