Simplify the following text for a Grade 6 native English-speaking person.
Original: In addition , students at the two schools can cross-register in undergraduate or graduate classes without any additional fees , for credits toward their own school 's degrees . Harvard is governed by two boards , one of which is the President and Fellows of Harvard College , also known as the Harvard Corporation , founded in 1650 , and the other is the Harvard Board of Overseers .
Simplified: Some of Harvard 's graduate schools are in Boston , but most of Harvard 's schools are in Cambridge .