to remove a covering like a curtain from a new structure at a formal ceremony in order to show the opening or finishing of a new building or work of art

The memorial to those who had died in the war was unveiled by the Queen. 缅怀战争死难者的纪念碑由女王揭幕。

If you unveil something new, you show it or make it known for the first time.

The company recently unveiled a test version of its new search engine. 这家公司最近公布了新搜索引擎的测试版。