Hello, everyone.<br/><br/>In the following quotation:<br/><br/>"<i>That being the case, AMD said it is "actively investigating" the cause and promises to provide another update <u>at</u> the conclusion of its investigation.</i>"<br/><br/>Source:<a href='http://www.maximumpc.com/amd_explains_performance_variance_among_retail_and_press_sample_radeon_r9_290x_cards' target='_blank' rel='nofollow'>http://www.maximumpc.com/amd_explains_performance_variance_among_retail_and_press_sample_radeon_r9_290x_cards</a><br/><br/>Would it be ok to substitute <i>at</i> with <i>on</i>? <i>upon</i>?<br/><br/>I would have expected to see <i>on</i> there: <b>when</b> the investigation is concluded, they will.. - that is, <i>when</i> = <i>on</i>.<br/><br/>Thank you.