血细胞是循环系统中最小的单位。

A blood ___cell is the smallest unit in the circulatory system.

癌细胞如果不治疗会迅速增殖。

Cancer ___cells can multiply rapidly if not treated.

伽马射线可以用来破坏癌细胞。

Gamma rays can be used to damage the cancer ___cell.