第3题: [单项选择]The ______ on a bank note is virtually invisible on a flat surface. A. watermelon B. watershed C. waterproof D. watermark 参考答案:D 答案解析:watermelon西瓜;watershed分水岭;waterproof雨衣;watermark水印。根据句子的含义,只能选watermark.
第33题: [单项选择]In the Roman Holiday, ______. A. people date with their valentine B. birds choose their mates C. people choose someone to be his/her sweetheart D. birds also have their holiday 参考答案:C 答案解析:[分析] 见文章第四段“The custom of choosing a sweetheart on this date...”,可知当时罗马这一节日的风俗是在这一日择偶;据常识,B只是人们的一种想象