1. First, you need to go to a sealed bottle, pour a certain amount of drinking water into the bottle, and add edible citric acid.

2. Add baking soda to the bottle.

3. Cover the bottle and shake it.

4. Add sugar and shake well again.

5. Pour the soda in the bottle into the glass.

6. Put the lemon slices into the rim of the cup, insert the straw, and a refreshing "homemade soda" will be ready. It would be better to refrigerate and reuse.