______ to his work resulted in his great success.
. The Smiths looked forward with hope ____ a chance to go abroad.
. Don’t forget ____ the magazine to the library when you finish ____ it.
. — Why were you so late for work today? — ____ to the office was not very easy this morning because of the traffic.
. ____ and out of breath, we reached the top of the mountain and stopped ____ the beautiful scenery.
. As a teacher, he has never given his students so difficult a problem ____ they can’t work out.