HELP! I have a question on identifying sentence errors

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1

<p>the blue book!
P190</p>

<p>Ms. Jordan proudly demonstrated he company's new product, a watch that flashes the time in lighted numerals when .pressing a button</p>

<p>the underlined parts are proudly, demonstrated, lighted, pressing a button, and no error</p>

<p>the answer is pressing a button</p>

<p>why!????</p>

<p>hope to hear your input.
thanks</p>

2

<p>that is a tough one.</p>

<p>well i think because the sentence is in the past tense: (demonstrated).
so it should be : (when a button is pressed.)</p>

<p>but I'm not 100 % sure about it.</p>

3

<p>^ he's right</p>

4

<p>yup stuck-on-1700 is right..</p>

5

<p>thank you !guys!</p>

<p>i also thought like that.........</p>