Peterson used to work in a remote mountain village school, which is only        on foot.

We need to spend more time researching these suggestions so that we can make a(n) _______ choice.

Thinking that her daughter was doing homework, the mother left the room, _____ . 

Please remain _________ until the plane has come to a complete stop.

 It’s quite _____ of beginners to forget to use an article before a noun.