adj.(小得)无法察觉的，感觉不到的

The change was so imperceptible that few people noticed it.
这个变化如此微妙，以至于很少有人察觉。
His smile was so subtle, almost imperceptible, yet it conveyed genuine warmth.
他的微笑非常微妙，几乎难以察觉，但却传递出真诚的温暖。
The aging process is imperceptible until one day you realize how much time has passed.
老化的过程是渐进的，直到有一天你才意识到时间流逝了多少。
The color difference between these two fabrics is almost imperceptible to the naked eye.
这两种面料的颜色差异肉眼几乎无法察觉。
Her reaction was so imperceptible that I couldn't tell if she was pleased or not.
她的反应太微妙了，我无法判断她是高兴还是不高兴。
The temperature dropped imperceptibly as night fell, making it colder without anyone noticing.
夜幕降临，气温悄无声息地降低，人们几乎没有察觉到寒冷的增加。
The thief moved with such stealth and imperceptibility that no one suspected his presence.
小偷行动得如此悄然无声，没有人察觉到他的存在。
The changes in his personality were so imperceptible that only close friends noticed them.
他个性上的变化如此微妙，只有亲密的朋友才能察觉。
The fading of the painting's colors over time was an imperceptible process, noticeable only upon comparison.
这幅画的颜色随时间逐渐褪去，这是一个只有通过比较才能察觉的过程。
His breathing became so shallow and imperceptible that we feared he might have stopped breathing altogether.
他的呼吸变得如此微弱和难以察觉，我们担心他已经停止了呼吸。