________ a walk is good for your health.
The volunteers many signs to remind people to protect the environment.
useful robot! It can help with the housework like a human servant.
It’s reported that there are more than 300 smokers in China, nearly a third of all the smokers in the world.
— May I watch TV now, mum?— No, you . You must clean your room first.
Mary used to in the countryside, but now she is used to in the city.