2. Pay attention to the writing unit, draw the ordinate and abscissa, and the date, name and "0" on the abscissa.

3. If the positions are limited, such as 0 to 10 and 20, if you write 200, the positions are absolutely limited. You can draw a wavy line on 0 and then write 100 (of course, other numbers are ok, but the most standard is to draw a lightning line).

For example, the picture above should have different colors. If there are no markers, the first one can be filled with shadows, the second one can be painted tightly or one can be painted without shadows.

Write a title at the top of each picture.

Composite bar chart:

The length of a straight bar indicates quantity.

Advantages: the figures can be seen clearly, and it is convenient to compare the figures of the two sets of data.