The possibility of a way out of the difficulty never _____ to the captain and his crew.

I think that this is the best mobile phone available in the world. No other one can ________it.

           , I lost heart in English learning, but my teacher often said to me, “Keep on studying hard , and you’ll succeed             .”

The room ____ voices of the children.

American people are wondering whether the newly-elected president and his administration will keep the nation safe and defend it _______ any terrorist attack in the future.