A few doubts

Hi,

• Which sentence is correct in the case of a letter, both formal and informal one? I am writing to ask/tell etc. or I write to ask/ tell etc.
• The school is organizing or The school are organizing? Is
• If I write a letter in order to ask some questions about an English course, and I enumerate several questions, can I use the word "finally" or "at last" with the last question? 'Finally' is OK. Don't say 'at last'.
   e.g. I have got some questions concerning the course and I hope you can answer. How much does the course cost? Could you tell me how many students are there in the group? Finally/at last, where can I stay?
• News spreads quickly or News spread quickly spreads
• I'm going on holiday to Italy  or I'm going to Italy for a holiday. Both are OK.
• Also: Where are you going for a holiday  or Where are you going on holiday? Both are OK.
• Is it correct? I haven't met him for a so long time. No. Say 'for such a long time'.
• Best wishes, Clive