imperceptibly
adv. 极微地；微细地；察觉不到地
例句
The disease develops gradually and imperceptibly.
该疾病难以察觉地逐渐发展着。
《柯林斯英汉双解大词典》
Slowly and almost imperceptibly the road started to climb upwards, looping its way in languid curves around the forested hills.
道路缓慢而几乎不可察觉地开始向上攀升，在林木环绕的山丘上曲折地蜿蜒前进。
Allopatric speciation can also be brought by the imperceptibly slow but colossal movements of the tectonic plates that make up Earth's surface.
构成地球表面的那些构造板块极其缓慢但剧烈的运动，也可能导致异地物种形成。
