<ol>
<li>In Germany, foresters discovered that trees killed by acid rain had begun to die four years (earlier, even though the trees had shown no signs of disease then).</li>
</ol>
<p>Why is it A - (as it is)?
Shouldn't there be an error in conjunction since [though] is not one of fanboys? So there shouldn't be a comma?</p>
<p>Commas aren’t necessarily JUST for Fanboys. In this case, “even though…” Is describing foresters & that’s why it needs a comma.</p>
<p>You only use FANBOYS when connecting two independent clauses. A simple comma can separate an independent from a dependent clause. “Even though” is a subordinating conjunction, and thus separating the dependent clause from the independent clause with a comma is appropriate.</p>
May I ask for the same question, if for the other answer " earlier without showing any signs of disease shown then" , why is it flawed? Thanks!
@Fairplay01 That version of the sentence keeps all the ideas in a single clause. This means that “four years earlier” and “then” are in the same clause. So “then” is redundant.
More obviously, putting “showing” and “shown” in the same phrase is redundant. (I don’t have the book; are you sure you typed that correctly?)