protaspis stage

例句：

1. 1. The researcher observed the protaspis stage in the sample.
   研究者观察到样本中的原虫阶段。
2. 2. This discovery sheds light on the protaspis stage of the organism.
   这一发现揭示了该生物体的原虫阶段。
3. 3. During the protaspis stage, the cells are highly motile and capable of rapid movement.
   在原虫阶段，细胞高度移动，能够迅速移动。