<ol>
<li>Although she considers her chemistry research (complete), she has heeded her professor's advice and is conducting three additional experiments. </li>
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<p>There is no error. But what's the difference between using 'complete' and 'completed' in the sentence? Both seem right</p>
<ol>
<li>Chess players find that playing against a computer is helpful (to improve) their skills, even though no chess-playing computer has yet won a championship</li>
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<p>Stuff in paranthesis is wrong. Why? Is it idiom "helpful in". There are too many idioms how am I supposed to remember them all?</p>
<p>for #2, is the correct modification “in improving”? If it is, then it is so because “improving” has to be parallel with “playing”. If it’s not right, then i don’t have any idea.</p>
<p>Hmm. I’m quite sure that “in improving” is correct, but I’m not sure why. I think using an infinitive is wrong there.</p>
<p>And yes, it’s complete, not completed. I’d say it’s because “completed” has to do with whether she’s done all the work or not, and not whether some additional element is needed to make the work “complete.”</p>
<p>And sadly, there’s no way you can remember all the idioms. You have to absorb them by reading lots of different kinds of good writing in English.</p>
<ol>
<li><p>Just because you can think of another way to word the sentence doesn’t mean that it’s grammatically incorrect.</p></li>
<li><p>“helpful to improve” is unidiomatic. The proper idiom is “helpful in [gerund],” in this case “helpful in improving.”</p></li>
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