aString := 'Now is the time for all good men to come to the aid of their blah blah blah'.

someWords := aString findTokens: ' '.

someWords indexOf: 'blah'.

"--> 16"

someWords replaceFrom: 1 to: 2 with: #('Then' 'was')

"--> OrderedCollection ('Then' 'was' 'the' 'time' 'for' 'all' 'good' 'men' 'to' 'come' 'to' 'the' 'aid' 'of' 'their' 'blah' 'blah' 'blah' )"

someWords copyReplaceAll: #('Now' 'is') with: #('Then' 'was' 'almost')

"--> OrderedCollection ('Then' 'was' 'almost' 'the' 'time' 'for' 'all' 'good' 'men' 'to' 'come' 'to' 'the' 'aid' 'of' 'their' 'blah' 'blah' 'blah' )"