Oh, boy, why are you killing your time this way? Can’t you find something _____ doing? 

— Have you read this book?　　　　— Yes. But that one is ________ worth reading.

As　an　excellent　shooter，Peter　practised　aiming　at　both＿＿targets　and　moving　targets．

 Since Margot found it difficult to settle in a new place, she felt ______ that the family had to move.

There were two boys in the lab, ________ did the experiment successfully.