One Grammar Question ^help

Test Preparation SAT Preparation
1

<ol>
<li>In 1850 Jim Beckwourth, a Black Hi, guys
I have a grammar question from official guide for a long time but still I cannot figure it out. I need yoou help.</li>
</ol>

<p>Here is the question</p>

<p>American explorer, discovered（A） in the(B) mountains of t he Sierra Nevada a pass soon becoming(C) an important gateway to(D) California gold-rush country. No Error (E) </p>

<p>Why choice C is incorrect? What about regarding 'becoming' as the post-modifier to modify the noun 'pass' ？ Is it said that 'soon becoming' should be replaced by 'which soon became'?</p>

2

<p><a href=“http://talk.collegeconfidential.com/sat-act-tests-test-preparation/1024015-writing-question-present-vs-past-participle.html[/url]”>http://talk.collegeconfidential.com/sat-act-tests-test-preparation/1024015-writing-question-present-vs-past-participle.html&lt;/a&gt;&lt;/p&gt;

<p>Try searching around. The answer to your question is yes, your last proposal is one way to correct the error in (C). In the present format, the sentence is a run on, and the “soon becoming” is in the wrong tense.</p>