On the third day (April 8) after the seeds were planted, the seeds sprouted in my expectation:

On the eighth day (April 13), it was lovely to see a new life. On the tenth day (April 15), the back was finally straight. On the twelfth day (April 17) and the seventeenth day (April 22) after the two leaves opened, most of the cotyledons of mung beans have fallen off, and the seedling height has also increased greatly. Yesterday it was only 7.8cm, so I will go again today.