单选题 He is ______ about his chances of winning a gold medal in the Olympics next year.
A. optimistic B. optional C. outstanding D. obvious

【正确答案】 A
【答案解析】[解析] 四选项的意思分别是：A．“乐观的，乐观主义的”；B．“可任意选择的，非强制的”；C．“杰出的，优秀的”；D．“明显的”。