Your sentence
Conozco+a+tu+hermano.
Words in this sentence
conocer
to know (a person or a place), to be familiar with, to be acquainted with; to meet; to get to know, become acquainted (with); to see, to visit, to explore (i.e., to get to know a place for the first time); to hear, to know (implies hearing for the first time); to discover, to get to or come to know, to learn about, to find out; to know, to have known; to know oneself; to conceptualize or conceive; to know, have sex with.
Verb
a
to; by; at; Used before words referring to people, pets, or personified objects or places that function as direct objects: personal a.
Preposition