SAT Question: Fixing a Comma Splice

Today's SAT Question of the Day addresses one of my favorite grammar errors: the comma splice. This happens to be one of the most common crimes against the English language committed by students in middle school and high school, but older folks do it, too.

So what's a comma splice? A splice is a connection. Think of an electrician that splices, or connects, two wires. A comma splice happens when you use a comma to join two independent clauses, which are clauses that could be sentences on their own. But remember: Commas are used for separating, not connecting, so a comma splice is a no-no.

So here's today's SAT question:

The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E.

It weaves across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S, the Panama Canal links the Atlantic and Pacific  Oceans.

The first step is to identify the comma splice. A sentence that's too much of a mouthful, like this one is, should raise a red flag that it's a run-on sentence. And many run-ons include comma splices.

This sentence contains two independent clauses. Each clause contains a subject and a predicate and forms a complete thought, so it could stand on its own as a sentence.

• It weaves across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S. 
• The Panama Canal links the Atlantic and Pacific Oceans. 

Luckily, there are always multiple ways to fix a comma splice.

Possible fixes:

• You can simply write two separate sentences. It weaves across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S. The Panama Canal links the Atlantic and Pacific Oceans.
• You can replace the comma with a semicolon (whose job really is to connect) to show that the two clauses are closely related. It weaves across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S; the Panama Canal links the Atlantic and Pacific Oceans.
• You can join independent clauses with a comma if one clause begins with a conjunction, which is a word that connects words, phrases or clauses.  As it weaves across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S, the Panama Canal links the Atlantic and Pacific Oceans.
• You can join independent clauses with a comma if one clause begins with a gerund, meaning a verb ending in '-ing'. Weaving across a strip of tropical land where the Isthmus of Panama narrows in the shape of a long, flattened letter S, the Panama Canal links the Atlantic and Pacific Oceans.

The only solution that makes sense for this particular SAT question is to replace 'it weaves' with 'weaving'.