第18题: [单项选择]He is ______ about his chances of winning a gold medal in the Olympics next year. A. optimistic B. optional C. outstanding D. obvious 参考答案:A 答案解析:optimistic (about)乐观的;令人乐观的:The public mood was optimistic and excited;optional可要可不要的;选修的(非必修的),如:Ou