Stomach ulcer More than 70 percent of duodenal and stomach ulcers are caused by a bacterium called helicobacter pylori.是什么意思_Stomach ulcer More than 70 percent of duodenal and stomach ulcers are caused by a bacterium called helicobacter pylori.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句