题目

I don’t________of your sending your daughter to Britain to study，because she is too young. A．agree               B．approve C．support             D．assess   答案：B考查动词辨析。根据空格后的of，可知选B。approve of同意；赞成。agree同意，赞成；support支持；assess评估，评定。  如图直三棱柱ABC-A1B1C1中，∠ACB=90°，AC=1，CB=，侧棱AA1=1，侧面AA1BB1的两条对角线交点为D，B1C1的中点为M．(Ⅰ)求证：CD⊥平面BDM；(Ⅱ)求平面B1BD与平面CBD所成锐二面角的大小．