“徒有其表”常见的英文表达有 “all show and no substance” 或 “have an impressive appearance but lack real value”。
“all show and no substance” 是一个比较简洁、常用的习语，直接传达了“只有外在表现，没有实际内容”的意思，与“徒有其表”含义高度契合。例如：This new product is all show and no substance; it doesn't work as advertised.（这个新产品徒有其表，根本不像广告宣传的那样好用。）
“have an impressive appearance but lack real value” 表达更具体、直白，清晰地描述出“外表给人印象深刻，但缺乏实际价值”这一含义。例如：The building looks magnificent, but in fact it has an impressive appearance but lacks real value.（这座建筑看起来很宏伟，但实际上徒有其表。）