I.选择填空（Vocabulary and structure）(共20小题，计20分)
A）从A、B、C、D四个选项中，选出可以填入空白处的最佳答案。（答案涂在答题纸上）
—Do you know Mr. Smith?
—Yes. He's a strange man. We found ________ difficult to work with him.
A. us               B. it             C. him            D. you