She didn't think _________ she did wrong that day. [ ]
A. that
B. what
C. which
D. if
答案:B
已知|a|=3,|b|=4,ab>0,则a﹣b=( ).
快速腰椎牵引的叙述,错误的是()
A.对后纵韧带骨化的患者应慎用
B.人工拉压复位法中,牵引每次重复3次
C.人工拉压复位法中,牵引的持续时间1~3秒
D.人工拉压复位法中,牵引重量约为体重的2~3倍
E.三维牵引治疗椎间盘突出,多数患者牵引3~5次即可