hello, nice to meet you

"sir" means ~님, ~각하, ~경. A very polite expressed. -ㅂ니까,이냐. is 《this, it, he》...?;are 《you, they》...?;do 《you》...?;《what》 is 《that》...?;《what》 does 《she》...? Is he a doctor? 그는 의사입니까? polite expressed 그는 의사인가? equal to or less than the dialog. Do you love her? 그녀를 사랑합니까? polite expressed 그녀를 사랑해? equal to or less than the dialog. --->This example, colloquial and written language is a little different. Hoping to help even a little.

It is just there are many styles. 해, 하다 - familiar speech (formal and informal). 해요 합니다 - polite speech

Do you mean the politeness level? Normally you use 시 after the verb and before the ending to make a verb honorific 저는 학교에 가요 I go to school 김 선생님 학교에 가세요 Mr Kim goes to school 김 선생님 학교에 가십니다 Mr Kim goes to school http://www.transparent.com/korean/tag/korean-politeness-levels/ http://people.cohums.ohio-state.edu/pyun7/K102_06/K102FACT%207.1%20&%207.2%20&%207.3%20&%207.5.pdf Copy the last two lines together