_______ eager to get access to the president, the boy in northern America wrote a letter to him.

 He put on his tie, took one last look at the room and_____________  walked out of the door.

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

When the expression first came into being, people refused （拒绝）to use it but _____ they began to accept it. 

If you smoke a cigarette every day, you will _____ become addicted to smoking．