二、单项填空（15小题，计15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。
15. ____ little tramp was ____ social failure but was loved for his optimism and determination to overcome all difficulties.
A. A, the B. The, a C. The, / D. A, /
16. They often change the kind of crop in each field ____ few years, for example, growing corn or wheat and then the next year peas or soybeans.
A. every B. a C. each D. some
