It’s helpful to put students in a situation _______ they can learn how to cooperate with each other.

I knew it was only a small operation but I couldn’t help feeling________. [ ]

Mom, must I put on the jacket—- _________. It’s kind of hot today.

The stranger shook me by the hand warmly ________ he were to say he knew me well.

Smoking can help you relax. But _______ it is also bad for your health.