It is one thing to enjoy listening to good music, but it is quite _________ to perform skillfully yourself.

They sometimes go on working ____ the light of the moon

The government has been under growing pressure to __________ the causes of air pollution as smog frequently cover over the country’s large cities.

How come ___________—I had to look after my sick brother.

Shall I tell John about it——No, you __________. I’ve told him already.