A lot of trees _________ around here every year, and we can enjoy fresher air now.
Look at the boy _______ yellow. ( )
如图,在直角坐标系中,四边形OABC是直角梯形,BC∥OA,⊙P分别与OA、OC、BC相切于点E、D、B,与AB交于点F.已知A(2,0),B(1,2),则tan∠FDE=____.
小科在学习了《家庭用电》后设计了一个如图所示的电路。下列相关说法正确的是( )