Your niece is very strict and ______ worth teaching, but your nephew is not. Look, he is now ______ asleep in class.

—Shall we go out for a walk?—Sorry. This is not the right ____ to invite me. I am too tired to walk. 

The research showed beyond ________ that smoking contributes to heart diseases.

Idioms are used all the time and unless you recognize when an idiom is being used, what you read or hear ______ can easily be misunderstood 

It ______ quite correct that happiness comes from thinking about things in a positive way.