Intervention is a type of Engagement. Engagement is a synonym of Date. Date is related to Proposal. 
Veteran is a type of Expert. Investigator is a type of Expert. Investigator is related to Agent. Agent is related to Air. 
Intervention --IsA--> Engagement <--Synonym--> Date <--RelatedTo--> Proposal 
Veteran --IsA--> Expert <--IsA-- Investigator <--RelatedTo--> Agent <--RelatedTo--> Air 