The air that surrounds our planet is both odourless , colourless, and invisible .
The phrase "keeps sellers on their toes" in the passage mostly means "______".
The examination was not very difficult, but it was_____________________ long.
As a millionaire who liked to show off her wealth, Mrs. Smith paid______________________________________________ we asked.
We must push the piano to the corner of the hall to_____________________ our party tonight.
______ his brother, Mike is active and friendly.
The boat was sailing north when a terrible storm_____________ .
The Lake District,____________________ was made a national park in 1951, attracts a large number of tourists every year.
Stephanie: "Oh, no! I left my book at home. Can I share yours?" Scott: "______ "
_______ has been a topic of continual geological research.
The pool should not be made so deep______small children can be safe there.