Răspuns :
1. We look forward to seeing you.
Closing remark, formal.
2. Hi, Just a quick note to tell you I'm having a party.
Opening remark, informal.
3. We cordially invite you to our annual summer party.
Opening remark, formal.
4. I can't wait to see you.
Closing remark, informal.
The first sentence is a closing remark and it is formal.
The second sentence is an opening remark and it is informal.
The third sentence is an opening remark and it is formal.
The forth sentence is a closing remark and it is informal.