题干
He proved himself a true gentleman and the beauty of his ________ was seen at its best when he worked with others.
A：advantage
B：appearance
C：qualification
D：character
答案(点此获取答案解析）
D
溶液至过量，同时加热，沉淀的物质的量先增多后减少，但最终仍有沉淀未溶解，在此过程中还有刺激性气味气体生成。