<p>Semicolons vs. commas:</p>
<p>Commas are used to connect an independent clause and a dependent clause. In other words: one complete sentence and one incomplete sentence. I don’t know if I have to get into what constitutes a sentence, but here are some examples:</p>
<ul>
<li>After the hospital had completed its fund-raising campaign (INCOMPLETE introductory phrase), a donor contributed an additional $10,000 (COMPLETE).</li>
<li>From the east wall to the west (INCOMPLETE introductory phrase), her cottage measures twenty feet (COMPLETE).</li>
<li>Yesterday was her brother’s birthday (COMPLETE), so she took him out to dinner (INCOMPLETE, since this begins with the conjunction “so”).</li>
</ul>
<p>Some conjunctions that commonly follow commas: because, or, and, although, so.</p>
<p>Semicolons connect two closely related independent clauses. Think of them as “stronger” than a comma but “weaker” than a period - they link the sentences together without separating them entirely like a period would. What they have in common, though, is that both parts on either side of a semicolon can also stand on their own. So if you’re not sure whether to use a semicolon or a comma, just stick in a period and see if it would work. If it can, you need a semicolon.</p>
<ul>
<li>Abdominal exercises help prevent back pain (COMPLETE SENTENCE); proper posture is also important (COMPLETE).</li>
<li>It rained heavily during the afternoon (COMPLETE); we managed to have our picnic anyway (COMPLETE).</li>
<li>The auditors made six recommendations (COMPLETE); however, only one has been adopted so far (COMPLETE).</li>
<li>They couldn’t make it to the summit and back before dark (COMPLETE); therefore, they decided to camp for the night (COMPLETE).</li>
</ul>
<p>Some conjunctive adverbs that commonly follow semicolons: however, nevertheless, thus, moreover, therefore, otherwise. Hope that helps!</p>