第一节 语法与词汇知识（共20小题；每小题1分，满分20分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡将该项涂黑。
1.The girl looked at me with a _____ expression. Maybe the problem was quite _____.
A. puzzled; puzzling B. puzzling; puzzled
C. puzzled; puzzled D. puzzling; puzzling
2.Without facts, we can’t form a correct opinion, for we need to have actual knowledge ____ our thinking.
A. which to be based on B. which to base on
C. on which to base D. which to base
