The use of conocer
In the sentence "Yo conozco el profesor de literatura" the "el" changes. Why is this change occurring and what is it changing to? Why must it change at all?
2 Answers
First of all it should be "Yo conozco al profesor de literatura.
When using the verb "conocer" you need the personal "a" before a name or any kind of "people word, like "profesor."
If it were a female professor, you would say "Yo conozco a la profesora de literatura.
"A" plus unstressed "el" contracts to "al."
So I know the professor of Literature (Or "I know the Literature professor.) becomes
Yo conozco al profesor de literatura.
BTW, the "Yo" is not necessary as the "O" ending on conozco indicates who the subject is.