题目

选词填空根据短文内容，用方框中所给单词的正确形式填空，使短文通顺、完整．每词限用一次 possible play one win trainMa Long is a member of Chinese table tennis team． April 28 was a big day for him． He【1】 his third straight men's singles title（单打冠军） at the World Table Tennis Championships（锦标赛 in Budapest． He became the 【2】 man in over half a century．Ma Long hurt his knee several months before the event． His doctor said it would be almost【3】 for him to play again． However， Ma didn't give up． Even with his injur据报道，某地发现一温泉，经检测分析，发现该温泉属于硅酸盐温泉，对心脏、高血压等有良好的医疗保健作用．已知硅酸盐中硅元素的化合价为+4价，则硅酸的化学式为（　　）A．H2SiO4B．H4SiO3C．H2SiO3D．Na2SiO3