Use the links here to find out about words.
The references in brackets are to the relevant pages in Mastering Practical Grammar (MPG), but you can equally use any other grammar book or site to develop your general knowledge before trying the exercises.
Open class words (MPG pages 9-10)
Closed class words (MPG pages 9-10)
Nouns (MPG pages 10-13)
Adjectives (MPG pages 13-18)
Verbs (MPG pages 18-26)