Special attention should be _____ to air pollution wherever the factory will be built.
When she came in, she found a stranger ______ at the back of the classroom with his eyes ______ upon her.
If you live in the country or have ever visited there, ______ are that you have heard birds singing to welcome the new day.
______ when we passed by its nest.
“Sorry” is the hardest word to say sometimes. _______ you know you’ve done something wrong, or something inappropriate, it takes courage to say sorry.
______ for the breakdown of the school computer network, Alice was in low spirits.