Once a year , people take part in “ ______ Lights ” activity to help save energy . 

Pollution is a serious problem. Scientists have _____ some good ways to save it. 

— Excuse me, would you be kind enough to 　　　 me your bike? — Sure. Here’s the key.

My car alarm is always______ whenever my neighbor's cat goes under my car.

Our teachers always tell us        fast when we go to or from school.