Use these resources to make sure that you are familiar with the parts of speech. This will help you to know how to build sentences correctly and make them more complex by using a variety of word classes.
Verbs
Nouns
Pronouns
Adjectives
Adverbs
Conjunctions
Prepositions
Articles
Auxiliary and Modal Verbs
Coordinating Conjunctions
Subordinating Conjunctions
Conjunctive Adverbs