modifies a noun or pronoun:

that box

wooden box

Ralph's box

three boxes

modifies a verb, adjective, or other adverb:

had run YESTERDAY ; had run AWAY ; had run QUICKLY

a VERY big tree ; REALLY serious

VERY quickly ; NEVER again ; SO hungrily

Conjunction

(definition and types)

joins two words, phrases, or clauses

2 kinds: coordinating conjunction (joins equals); subordinating conjunction (joins depended clause to independent clause)

COordinating conjunctions are:

AND BUT OR NOR FOR

Conjunctive adverbs are regarded as ADVERBS.

A semicolon and a comma are used together when a conjunctive adverb separates two main clauses:

I wanted to go; however, I was too busy. 

connects a noun or a pronoun to the rest of the sentence, showing some relationship: prepositions ALWAYS OCCUR IN PREPOSITIONAL PHRASES: there will always be an object (a noun or pronoun) of ever preposition. 

ex. He glanced into the box. "Into" is the preposition; "box" is the object. 

may; can; must; might; shall; will; should; would; could; have; do; be

have includes: has, had, having

do includes: did

be includes: am, are, is, was, were, being, been