【单选题】如图所示,两块平面镜相交,一束光线沿AO斜射到平面镜MP上,并且与平面镜的夹角为30°,光线经两平面镜反射后与AO重合,但方向相反,则两块平面镜的夹角α是( )
【单选题】如图,平面α⊥平面β,A∈α,B∈β,AB与两平面α、β所成的角分别为 和 ,过A、B分别作两平面交线的垂线,垂足为A′、B′,则AB:A′B′= [ ] A、2:1
【判断题】We fix problems and make decisions every day.
【简答题】如图,平面 平面 , 与两平面 、 所成的角分别为 和 。过A、B分别作两平面交线的垂线,垂足为 、 若AB=12,则 (A)4 (B)6 (C)8 (D)9
【判断题】插花容器的色彩越鲜艳,越能和鲜花协调统一。
【单选题】依据企业所得税法的规定,无形资产的摊销年限不得()。
【单选题】F: Diego, have we received a fax from Chris at Complex Computers yet?M: We did, but it came through blurry. I called, and Chris said they were having problems with the fax machine. They’re trying to f...
B.
The quality of the fax machines
C.
The service contract for Office PCs
【单选题】F: Diego, have we received a fax from Chris at Complex Computers yet?M: We did, but it came through blurry. I called, and Chris said they were having problems with the fax machine. They’re trying to f...
【简答题】如图,平面α⊥平面β,A∈α,B∈β,AB与两平面α、β所成的角分别为 和 ,过A、B分别作两平面交线的垂线,垂足为A′、B′,则AB:A′B′=( )。