Correct me please

0"During inspection, the items were found to pertain to another invoice." 0-

0 Sir, 02br
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00What difference do they make? 02br
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001. "While on" and "During" 02br
002. "Other" and "Another" 02br
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00Can I rewrite as below? 02br
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00While on inspection, it was found that the items pertained to another invoice. 02br
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00msn. 0-

0#1. 'On inspection' is a military phrase; it is not used of inventory. 02br
00#2. 'another' is for singular indefinite countables: 'another invoice', 'the other invoice', 'other invoices'. 0-

0 Thank you, Sir, 02br
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00I think it would take ages for me to really master in english language. The more I care about grammatical aspects the more I confuse. 02br
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00I wonder I will never able to speak english, If I concentrate more on grammer aspects. 02br
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00What do I do? 02br
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00msn. 0-

0It does take ages to 'really master' a language. I've still got a good distance to go myself. 02br
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00You can, however, separate the grammar and structure study from the speaking. Grammar requires sit-down-and-study, while speaking requires get-out-and-practice. You need to do both, but try to do one without worrying too much about the other. Eventually they will com