A:3种
B:4种
C:5种
D:6种
如图,AB⊥AC,AD⊥BC,垂足分别为A,D,则图中能表示点到直线距离的线段共有( )
关于光现象,下列说法正确的是( )
A. restaurant B. company C. library D. driver E. policeman F. policewoman
⑴ ____ ⑵ ____
⑶ ____ ⑷ ____
⑸ ____ ⑹ ____