人们在切葱时,眼睛常被刺激得酸痛流泪.这是因为葱内含有一种叫丙硫醛氧化硫的物质.当葱被切开后,这种丙硫醛氧化硫挥发得很快,进入人眼睛里,立即生成一种低浓度的亚硫酸,刺激得眼睛流泪. When people cut the onion, the eyes are often irritated and sore, because the onion contains a substance called propylthiourea and sulfur oxide.When the onion is cut, the sulfur oxide of the thioacetone volatilizes rapidly, Into the human eye, immediately generate a low concentration of sulfurous acid, stimulate the eyes to tears.