Grammar Without Tears: Ways & Means for Writing with Precision and Pccuracy

"The seminar not only endeavors to refresh and refine the participants’ existing knowledge on the subject but also underlines the ways and means for writing with precision and accuracy. The seminar tackles some of the nagging grammatical dilemmas that we all very often experience in our day-to-day lives while writing.
Which is a grammatically correct expression in the following:
 I have gone to Dubai Or I have been to Dubai
 I look forward to reading your book Or I look forward to read your book
 I met the concerned clerk Or I met the clerk concerned
 I am a teacher, is n’t it? Or I am a teacher, am n’t I? Or I am a teacher, aren’t I?
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