pallidum

例句：

1. 1. The patient's complexion was so pale that it was hard to tell if he was ill or just tired.
   病人的脸色非常苍白，很难判断他是生病了还是只是累了。
2. 2. The scientist discovered a new type of pallidium that could be used to treat cancer.
   科学家发现了一种新的苍白质，可以用来治疗癌症。
3. 3. The pallidum in the center of the painting is the most important part of the work.
   画中中心的苍白部分是这幅作品最重要的部分。