Alone in the lab on Sundays, the young scientist was so busy with his research work that he felt _____ but lonely.
Her ________ look suggested that she was very _______ with the answer.
This book is well worth _______. Would you like to buy one?
I have bought two ball pens , _______ writes well.
------Why do you turn back? ------ Oh, the bridge ahead_______.
People in the west make_______ a rule to buy Christmas presents for their relatives and friends.