— May I speak to Mary? — This is ________ speaking. 

Teenagers are warned to be careful when making friends online, because when you can’t see a person, they could be __________.

The sunspot came into its active stage, ____ that happens once every eleven years.

Looking at a situation in a new way will make _______ easier to find new solutions.

—What do you think of the songs? —In fact, ________ of them sounds beautiful.