I like __________in the early morning when the air is fresh and I can take a walk around the garden. 

To stay awake, he finished a cup of coffee and ordered     .

I ’ve made _____a habit to sleep early and rise early, which enables me to keep energetic .

I’m moving to the countryside because the air there is much fresher than ________ in the city.

 Computers must be of great use to ________ doing the scientific research.