Having checked the doors were closed,and_______all the lights were off,the boy opened the door to his bedroom.

Rather than _______ on a crowded bus, I always prefer _____ an electric bicycle

Some people do some _____work without getting any money in return . These people are called volunteers.

__________ that Maric was able to set up new branches elsewhere.

The reason why he adapted to the new situations quickly is that he has a _____ attitude.