For example, in chemical experiments, whether to turn off the lights or pull out the catheter first when making oxygen, why purify hydrogen and test the air tightness? Give you a substance to tell you the nature and let you infer; For example, calculation is also tricky.

C+O2=CO2

12 44

6 X then X=(44*6)/ 12 X=22.

These are all accumulated by yourself for a long time, and this is your problem-solving model.

In addition, there are typically summary examples in each part of the learning materials.