differentiation period of cell的用法和样例：
- Let us hope that the period of this injustice will be over soon.
- Childhood is a period of rapid growth.
- The area of cell line HFE-145 increased significantly after 12h simulated weightlessness (P<0.01), but did not change significantly in other period of time, the ratio of long and short diameter did not change significantly in all period of time.
- Which period of history are you studying?
- This was the most difficult period of his life.