@ the one below: who is alone? never I think I am alone, and I don't understand what you are talking about... btw, thanks for sharing.

@ the one below: who are you?

I don't know your teacher but I disagree with his/her judgement. I do not use skype. Yes, it's time to say "good night".

I did not mean to send the previous message 3 times.

The two words "neccesary" and "needed" are very similar. Most of the time they can be used interchangeably. However, in some cases there is a slight difference between them where "necessary=must be done" and "needed=required for the purpose of". You may find the information in this link helpful: http://www.usingenglish.com/forum/ask-teacher/71188-necessary-vs-needed.html