Note is related to Informal. Informal is a synonym of Casual. Casual is a synonym of Unexpected. Unexpected is a synonym of Random. 
Bus can be used for Trip. Trip is related to Acid. Acid is a synonym of Dot. 
Note <--RelatedTo--> Informal <--Synonym--> Casual <--Synonym--> Unexpected <--Synonym--> Random 
Bus --UsedFor--> Trip <--RelatedTo--> Acid <--Synonym--> Dot 