语法与词汇 16.He always included something above the understanding of his hearers in order to prevent them from becoming______and to stimulate their desire to learn more.
【正确答案】 B
【答案解析】四个选项的意思分别是：pessimistic厌世的，悲观的；complacent得意的，自满的；perplexed困惑的，混乱的；complicated麻烦的，复杂的。根据句意，应该选择B。