John had been sitting, unobserved, in the darkness.约翰一直坐在黑暗中, 没人发觉。

Looking round to make sure he was unobserved, he slipped through the door.他环顾四周确认没人看见, 便从那扇门溜走了。

I managed to sneak upstairs unobserved.我设法悄悄溜上了楼。

The change was so slight that it passed unobserved.变化太细微了, 因此没人注意到。