题目

7.如图，正方体AC1的棱长为1，过点A作平面A1BD的垂线，垂足为点H.则以下命题中，错误的命题是 A.点H是△A1BD的垂心                   B.AH垂直平面CB1D1C.AH的延长线经过点C1                  D.直线AH和BB1所成角为45° 答案：答案:D解析:AH与BB1所成的角即AH与AA1所成的角,可知cos∠HAA1=. I' d rather you ________ anything about it for the time being. [　　] A．doB．didn't do C．don'tD．didn't