Question

why did scientists struggle for thousands of years to accurately describe the solar system?
venus has phases like the moon.
many people spoke italian and did not understand latin.
the planets appeared to move backward in the sky occasionally.
scientists could not explain why the sun appeared to rise and set every day.

Explanation:

The retrograde motion of planets was a major puzzle for ancient scientists. Observing planets seem to move backward in the sky was hard to explain in early - conceptions of the solar system, causing long - term struggle to accurately describe the solar system. Venus having phases was actually evidence for a heliocentric model later on. Language (Italian/Latin) is not a key factor in understanding the solar system. The Sun's rising and setting is a daily observation easily explained by Earth's rotation and was not a major hurdle in understanding the solar system's structure.

Answer:

The planets appeared to move backward in the sky occasionally.