Seal is related to Sea. Sea is related to Swimming. River can be used for Swimming. 
Dumb is related to Sheep. Sheep is related to Sleep. Sleep is the opposite of Wake. 
Seal <--RelatedTo--> Sea <--RelatedTo--> Swimming <--UsedFor-- River 
Dumb <--RelatedTo--> Sheep <--RelatedTo--> Sleep <--Antonym--> Wake 