<p>These are from the wednesday 2004 PSAT/ 2006 practice book:</p>
<ol>
<li><p>Aerial photography is thought 'to be' 'the most efficient' technique 'to gather' accurate 'information about' the use of the land. 'No error'</p></li>
<li><p>Without consistent records we cannot determine 'which changes in the unemployment rate are attributable to seasonal' business fluctuations.</p></li>
</ol>
<p>What is wrong with replacing with "where change occurring the unemployment rate is an effect from seasonal"</p>
<p>The phrase you suggested for substitution makes no logical or grammatical sense. The change doesn’t occur the unemployment. “occur” is an intransitive verb; nothing can be occured.</p>
<p>1 is C. most people put E when this test was given. “for gathering” describes a purpose whereas “to gather” describes a motion. the “to” in “to gather” means “in order to,” but there is no preceding verb (i.e. “technique used to gather”) to complement it</p>