Do you know ___________ Zunyi or not tomorrow?
A:whether are they leaving for
B:whether they are leaving for
C:if they are leaving for
D:if are they leaving for
随着经济建设的发展,我国的民主政治建设也加紧进行,我国第一部社会主义类型宪法诞生,制定这一法律文件的会议是( )
当公民受到不法侵害时,最佳方法是( )
如图,三棱柱ABC﹣A1B1C1的底面是边长为4正三角形,AA1⊥平面ABC,AA1=26,M为A1B1的中点.
(Ⅰ)求证:MC⊥AB;
(Ⅱ)在棱CC1上是否存在点P,使得MC⊥平面ABP?若存在,确定点P的位置;若不存在,说明理由.
(Ⅲ)若点P为CC1的中点,求二面角B﹣AP﹣C的余弦值.
简答山顶洞人比北京人有哪些进步?