All the people in the nation can remember exactly how many years ago _______ the civil war broke out.
Many kinds of birds fly south at the ______ of winter.
At the meeting they discussed three different _____ to the study of maths.
The bald eagle_____ the United States.
It was difficult to guess what her _____ to the news would be.
—How do you _____ to her unkindly behavior? —Only silence. Which of the following is wrong?