Group 1 (ought, aught)
    
buy-bought-bought 
bring-brought-brought 
catch-caught-caught 
fight-fought-fought 
teach-taught-taught 
 think-thought-thought


Group 2 (ew-own)
fly-flew-flown 
grow-grew-grown 
 know-knew-known
Group 3(d-t)
                           feel-felt-felt 
               spend-spent-spent 
               send-sent-sent 
               keep-kept-kept 
               leave-left-left 
               build-built-built

Group 4 (a-u)
begin-began-begun 
run-ran-run 
drink-drank-drunk 
sing-sang-sung 
swim-swam-swum

get-got-got   put-put-put
Group 5 (2=3)
     have-had-had 
     set-set-set 
     read-read-read 
     make-made-made 
     lead-lead-lead 
     meet-met-met 
     find-found-found 
     stand-stood-stood 
     tell-told-told
Group 6 (en)
                choose-chose-chosen 
                   eat-ate-eaten 
            forget-forgot-forgotten 
            give-gave-given 
            take-took-taken 
              speak-spoke-spoken 
           steal-stole-stolen 
           write-wrote-written 
shake-shook-shaken 
wake-woke-woken 
hide-hid-hidden