Dear Sir, Dear Mr. Smith, Dear John or Hi John.... how can you decide how formal your email should be? And what are the differences between formal and informal English? Watch this video to find out, then click here for practice: http://bit.ly/EmailUnit4 For more, don't miss Writing Better Emails, our online course, starting 1 October: http://bit.ly/BetterEmails2 Neil | LearnEnglish – British Council