. It’s true that he did write some excellent poems, but he is ______ known as a playwright. 

It is good for elderly people to be _________ involved in community service.

As is known to all language learners, the newly learnt words will soon be forgotten unless ______ used in everyday communication.

Suan! Where have you been? You have no idea ___ worried I was !

New digital mobile phones definitely produce less radiation, but that doesn’t ______ mean that they should be used without caution.