Operator is related to Machine. Machine is the opposite of Human. you are likely to find Mouth in/at/on Human. Mouth is related to Call. 
Swear is a synonym of Trust. Friend can Trust. Friend is related to Letter. Letter is related to Love. 
Operator <--RelatedTo--> Machine <--Antonym--> Human <--AtLocation-- Mouth <--RelatedTo--> Call 
Swear <--Synonym--> Trust <--CapableOf-- Friend <--RelatedTo--> Letter <--RelatedTo--> Love 