Answer:
His music was based on what he saw in his life.
Step-by-step explanation:
Woody Guthrie's music caught the contrasting emotions of America and how people manage to survive and thrive in impossibly difficult times, so the phrase "All you can write is what you see" shows that he writes his music based on what he has experienced first hand or from the experiences of others.
It shows that Woody Guthrie put his pen to paper on what he saw in life.