Root is a synonym of Drill. Drill is a type of Teach. Lecture is a type of Teach. Preach is a type of Lecture. 
Discover is related to Adventure. Adventure is related to Explore. Pioneer is a type of Explore. Pioneer is a type of Introduce. 
Root <--Synonym--> Drill --IsA--> Teach <--IsA-- Lecture <--IsA-- Preach 
Discover <--RelatedTo--> Adventure <--RelatedTo--> Explore <--IsA-- Pioneer --IsA--> Introduce 