o: soon, to and good
Long o in ME becomes u in PDE.  "Good" is not exactly an exception, because the vowel did rise in the GVS; however, after rising, it became lax U.
 
 

	ME	PDE
"to"

 

pseudo-exception	ME	after shift	PDE
"good"

Check out all the changes in the words  |  What is PDE?