.Did you have trouble_________the entrance to the hill ?
1. It is difficult to __________ one twin from the other.They almost don't __________ from each other.
—May I open the window to let in some fresh air?—__________.
When I saw the beautifully decorated house, I really wondered __________ she could manage that all by herself.
I__________ it to my parents that I have lived through those hard times.
To understand the grammar of the sentence, you must break it __________ into parts.