I haven’t finished my homework .
---Why is he so happy? ---He __________ the volunteering club and works for the old people.
---The girl is practicing English, ___________? ---Yes, she is. She is good at English.
---___________ tall building it is! ---It has over one hundred floors.
Look at the picture. We are supposed to____________.
More and more people have a low-C life and the air is _________ than before.