Final answer:
The teacher is evaluating the accuracy of the dates on the poster by assessing how well they align with historical events.
Step-by-step explanation:
The teacher means that they will be evaluating your poster based on the accuracy of the dates you have included. Specifically, they are assessing how well the dates on your poster align with historical events. This means that the dates on your poster should accurately represent the timeline of historical events. In other words, the teacher wants to ensure that your poster accurately reflects the historical context.