Happen (verb) vs Coincidentally (adverb) 
Wrong (adjective) vs Unexpectedly (adverb)
Hit (verb) vs Suddenly (adverb) 

Examples
Happen vs Coincidentally
Verb: Games happen during the summer.
Adverb: Coincidentally I won the game. 

Verb: Rain happened yesterday.
Adverb: Coincidentally it is raining now.

Wrong vs Unexpectedly
Adjective: They brought the wrong laptop. 
Adverb: Unexpectedly the laptop broke down. 

Adjective: I deleted the wrong number. 
Adverb: Unexpectedly I deleted the number.
 

Hit vs Suddenly
Verb: The phone fell and hit the floor. 
Adverb: Suddenly I lost the phone. 
​
Verb: I saw the lightweight strike. 
Adverb: Suddenly I saw lightning.