Formal vs Informal Communications

Which expression is formal?

• Dear Mr Smith,

• Hi dude!

Which expression is informal?

• I'm sorry I haven't written for ages.

• I apologize for not getting in contact with you before now.

Which expression is informal?

• How's it going?

• Further to your last letter...

Which expression is NOT informal?

• I am writing with regard to...

• Listen! Did I tell you...

• Just a note about...

• Oh, another thing...

Which expression is NOT informal?

• Write soon.

• If you require any further information, please do not hesitate to contact me.

• Hope to hear from you soon.

Which expression is NOT informal?

• Yours sincerely,

• Best regards,

• Love,

How would you greet this person?

• Good morning. 
• Hey. 

How would you greet this person?

• Hey there. 
• Hello. How are you? 

How would you greet this person?

• What's happening?
• Good evening. 

Formal or informal: Harry Potter books rule!

• Formal
• Informal