(本小题满分12分) 如图,菱形的边长为,,.将菱形沿对角线折起,得到三棱锥,点是棱的中点,. (Ⅰ)求证:平面; (Ⅱ)求证:平面平面; (III)
如图①,△OAB中,A(0,2),B(4,0),将△AOB向右平移m个单位,得到△O′A′B′. (1)当m=4时,如图②.若反比例函数y=的图象经过点A′,一次函
设为奇函数,且在内是减函数,,则的解集为( ) A. B. C. D.
弹簧振子在振动过程中振幅逐渐减小,这是由于( ) A.振子开始振动时振幅太小 B.在振动过程中要不断克服外界阻力做功,消耗能量 C.动能和势能
Look! Peter TV happily, but his parents are busy in the kitchen. A. is watching B. watches C. watched
唐朝为什么以胖为美王彬 ①如果去观赏唐代绘画、雕塑、陶俑及其他各类艺术作品所表现的女性形象,留给大家最突出的印象,也一定是“丰肥浓
My husband and I were paying a visit 61 my parents in Tucson. We went to a fast-food restaurant for dinner together. My husband went to the counter 62 (order )dishes and I s
阅读甲、乙两则文言文,完成1~4题。 [甲] 嗟夫!予尝求古仁人之心,或异二者之为,何哉?不以物喜,不以己悲;居庙堂之高则忧其民;处江湖之远则