Douglass, with the ability to read, learned that slavery was imposed on him.
Step-by-step explanation:
At one point in time, Douglass was a slave. Slaves at that time did not know how to write or read, unlike Douglass. He read the book, 'The Columbian Orator', in which he read the conversation between the master and his slave.
By reading the book Douglass assumed him as the slave and others were set free from slavery. So, he decided not to be a slave for a long and need to be set free.
Also, he believed that his condition was not good and started thinking of ways by which he and other slaves could get freedom.