It _______ seven years __________ Hong Kong returned to China.

To ____ nature is to help ourselves, or we will be punished.

---How do your parents usually go to work?---My mother usually goes to work _________  bus while my father ________ a bike to work. 

It was very hard for me to make a _________, but I decided to leave my job.

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