5.3 Punctuating Complex Clauses
There are several different ways to combine two independent clauses into a longer, coordinated clause. Lesson 5.4 introduces the idea of differing punctuation resulting in different meanings. (For a review of how to identify independent clauses, see Lessons 2.1, 2.2, and 2.3.)
One way to conjoin two independent clauses is to use a coordinating conjunction. There is a small group of these in English (for, and, nor, but, or, yet, and so, which you can remember with the acronym FANBOYS). When you use one of these, you simply put a comma after the first clause and before the conjunction.
[I really want to sleep late this morning], and [I really don’t want to go to school].
[My sister wants a dog], but [she also wants a cat].
However, some usage guides will tell you that when the independent clauses are “short,” commas aren’t necessary. But what’s short enough? It’s not necessarily clear.
Boo ate lunch, but Roo didn’t.
Boo ate lunch but Roo didn’t.
Either of these ways of punctuating is acceptable, but since they each contain two independent clauses and a conjunction, it’s always going to be considered correctly punctuated to have the comma.
Coordinating conjunctions don’t only conjoin clauses, they conjoin all of the other content categories, such as nouns (dogs and cats), adjectives (big and tall), adverbs (quickly but sloppily), verbs (running or skipping). And conjunctions always conjoin two phrases of the same category. Similarly, correlative conjunctions (like either…or, see Lesson 2.9) compare two like categories.
Semicolons too can be used to conjoin independent clauses, but then a conjunctive adverb comes in between them, not a conjunction. Conjunctive adverbs are words like however, therefore, thus, consequently, hence, furthermore, indeed, or likewise. Such clause linkers are common in formal academic English.
Boris attempted to climb the wall; however, he failed.
You can also use a semicolon without a conjunctive adverb.
Boris attempted to climb the wall; he failed.
But you cannot have simply a comma with the coordinating conjunction. That is called a comma splice or a run-on sentence, and is considered a fairly serious error in most forms of writing.
not ok: Boo ate lunch, Roo did not.
Using the following pairs of simple clauses, combine them in two different ways, using first a semicolon and a conjunctive adverb and then a comma and a conjunction.
We walked to the store. We bought marshmallows.
It is important to always wear a seatbelt. Seatbelts save lives.
Walking to work is good for the environment. It is good for your health.
My cousins arrived from Missoula. We were excited about their visit.
key words: punctuation, commas, semicolons, independent clause, coordination, coordinating conjunction, conjunctive adverb
CCSS.ELA-Literacy.L.3.1h Use coordinating and subordinating conjunctions.
CCSS.ELA-Literacy.L.3.1i Produce simple, compound, and complex sentences.
CCSS.ELA-Literacy.L.4.1f Produce complete sentences, recognizing and correcting inappropriate fragments and run-ons
CCSS.ELA-Literacy.L.4.2c Use a comma before a coordinating conjunction in a compound sentence.
CCSS.ELA-Literacy.L.5.1a Explain the function of conjunctions, prepositions, and interjections in general and their function in particular sentences.
CCSS.ELA-Literacy.L.5.6 Acquire and use accurately grade-appropriate general academic and domain-specific words and phrases, including those that signal contrast, addition, and other logical relationships (e.g., however, although, nevertheless, similarly, moreover, in addition).
Here is this lesson as a pdf.