<p>1) The primatologist has argued that sustained observation of a few animals provides better behavioral data than does intermittent observation of many animals. </p>
<p>I revised the underlined part as option E, "in contrast to intermittent observation of many animals, provides better behavioral data."</p>
<p>However, the answer is A - leaving the sentence as it is. Can someone explain what is the technical explanation? </p>
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<p>2) If he HAD BEGUN (A) EARLIER (B), he might have succeeded IN FINISHING (C) the EXTREMELY (D) complex project before the deadline. No error (E)</p>
<p>I thought A was incorrect as I believed it should be "began" but the answer is E, no error,</p>
<p>Why? When do I use had begun or began? I'm really confused about this.</p>
<p>THANKS!</p>