(单词翻译:单击)
White blood cells, which are part of the immune system, and platelets, which help with blood clotting at a site of injury, also float in plasma.
白细胞是人体免疫系统的一部分而血小板则在人体伤口处起到凝血作用，这两种血细胞也都漂浮在血浆上。
They have much shorter life spans than red cells and also are replaced continuously.
但是它们的存活周期要比红细胞短，同时也会被不断地更新。
If you've ever seen a bone cut crosswise, with soft tissue called marrow inside, then you've seen where blood cells are made.
如果你看到过一块被横切的骨头，你就会看到里面的软组织，即骨髓，它是专门制造血细胞的。
Bone marrow contains special blood cells, which constantly divide to produce new cells to replace the ones that have been destroyed.
骨髓含有特殊的血细胞，这种细胞会不断分离产生新的细胞来取代那些已被破坏的细胞。
Why all this bloody business in the bone marrow?
为什么所有的造血工作都在骨髓中进行呢？
The body's process of forming new blood cells helps you recover if you lose blood to an injury,
答案是如果你因受伤而流血的话，人体生成新血细胞的过程便能帮助你复原，
and it also helps blood perform its many functions despite cell damage and loss.
同时，尽管存在细胞受损或缺失，这个过程也能帮助血液发挥很多其它的功能。
译文来自可可英语
