一、单项选择20%（每小题1分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳答案。
1. After the class was _____, some of the students went to the playground, playing basketball.
A. at an end B. in the end C. by the end D. at the end
2. They work day and night; however, _______ of the money they make goes to their so-called eldest brother.
A. four-fifth B. four-fifths C. four-five D. four-fifthes
