It is so soft that it can be easily scratched with the thumb nail.

铅的质地特别软, 用大拇指的指甲就很容易划出痕迹。

I do assure you it was not, at first, bigger than my thumb nail, and I am certain it has not grown any since.

我向你保证，最初那块比我的拇指指甲大不了多少，我肯定之后也没再长得更大。

He saw the wrinkles on her face; saw the artificial arrangement of her hair; the pointed elbows, and, above all, her large thumb nail, resembling that of her father.

他看到了她脸上的皱纹；看到了她头发的人工排列；尖尖的肘部，最重要的是，她的拇指指甲很大，很像她父亲的指甲。