But we will find from the concept-sememe tree of concept "医生(doctor)" that the father node of concept node "agent={~}" is "NONAME={doctor|医治}"，and so to the concept-sememe tree "护士 (nurse)", the father node of "agent={~}" is "NONAME={doctor|照顾}"，that is ,their corresponding father nodes are different, so we consider the concept node "agent={~}" of concept "医生(doctor)" is different from that of concept "护士(nurse)" in structure.
in these two concepts with five concept nodes, the same number of concept nodes is three, which is the most important reference to similarity computation between concepts.