1. Conjunctions

2. Three types of conjunctions
Coordinating-connects words used in the same way.
Correlative-pairs of words that connect word used in the same way.
Subordinating-used to begin subordinating clauses or adverb clauses

3. Coordinating conjuctions
For
And
Nor
But Or
Yet So
Use these to combine two subjects, two predicates, two clauses. The words/phrases/clauses you are combining must be the same!

4. Correlative conjunctions
Used to join subjects, objects, predicates, and other sentence parts.
Common correlative conjunctions
Both…and
Either…or
Neither…nor
Whether…or
Not only…but also
Example: Their eye lenses are not only long but also cylindrical.

5. Subordinating Conjunctions
After
As soon as
In order that
Until
Although
As though
Since
When As
Because
So that
Whenever
As if
Before
Than
Where
As long as
How
Though
Wherever
As much as If
Unless
While

6. Subordinating Conjunctions
Some of the subordinating conjunctions are also prepositions. BE CAREFUL.
Examples:
Before the sun had risen, we left for the cabin.
Before is the subordinating conjunction. The subject of that clause is sun; the verb is had risen.
Before sunrise, we left for the cabin.
Before is a preposition in this sentence.