“公开宣称”常见的英文表达有 publicly declare、openly proclaim 或 publicly assert，具体使用可根据语境和表达侧重点选择：
publicly declare：强调在公开场合或向公众明确表达某种观点、立场或意图。例如：
The company publicly declared its commitment to environmental sustainability.（公司公开宣称致力于环境可持续发展。）
He publicly declared his support for the new policy.（他公开宣称支持这项新政策。）
openly proclaim：“proclaim”有正式宣告、宣布的意思，“openly”强调公开地、毫不掩饰地，“openly proclaim”带有一种较为正式、庄重且毫不隐瞒地宣告的意味。例如：
The leader openly proclaimed the country's new strategic goals.（领导人公开宣称了国家的新战略目标。）
They openly proclaimed their opposition to the war.（他们公开宣称反对这场战争。）
publicly assert：“assert”有断言、坚决主张的意思，“publicly assert”侧重于在公开场合坚定地表达某种观点或主张。例如：
The scientist publicly asserted that his research findings were accurate.（这位科学家公开宣称他的研究结果是准确的。）
She publicly asserted her rights in the face of injustice.（面对不公正，她公开宣称了自己的权利。）