underneath常常用來代替under,特別用來表示完全或幾乎完全隱蔽時,如:mines underneathe the city 城市之下的礦井
under是用來表示最平常的方位上面的“下”
eg:under the bed,under the bridge
underneath則更加側重 “覆蓋”這種有外力存在的情況
eg:The letter was pushed underneath the carpet
另外,在句末的通常用underneath
eg:She wears a read coat with a blue dress underneath