填空题 Before he went to elementary school, Nixon had become a keen reader of 1, 2, and 3.

  • 1、
【正确答案】 1、children's encyclopedias，historystories，adult periodicals。    
【答案解析】[详细解答] 本题答案见文章第三段的结尾处，Nixon在五岁的时候已经成为儿童百科全书，历史书和成人期刊读物的忠实读者。