一、单句语法填空。
阅读下面每句话，在空白处填入适当内容（1个单词）或括号内单词的正确形式
1. It’s already 10 o’clock. I wonder how it ________ (come)about that she was two hours late on such a short trip.
2. —What are you doing this afternoon? Do you have any plans?
—Nothing ______ particular. I thought I’d just walk around downtown and look at the stores.
