一个星期后，观察该洋葱的改变。记得在这期间，需要为洋葱换上干净的水。

一个星期后，观察该洋葱的改变。记得在这期间，需要为洋葱换上干净的水。

Results (English) 1:

A week later, observed changes in the onion. I remember this period, we need to put on clean water for the onions.

Results (English) 2:

After a week, observe the onion change. Remember that during this time, you need to replace the onion with clean water.

Results (English) 3:

After a week, observe the change of the onion. Remember that in the meantime, you need to change the onions into clean water.