turn to ashes (化为泡影) 中的ashes不能用单数。句子结构应该是：状语从句：when they found （that）a beautifully-cooked wallet and notes turned to ash!【句子成分分析】they状语从句的主语；found状语从句的谓语;?（that）宾语从句的引导词，不充当成分，可以省略；a beautifully-cooked wallet and notes宾语从句的主语；turned to ash 宾语从句的谓语 这是新概念的课文中的句子。