Oracle Project Accounting Analyst interview questions

1. Basic accountancy questions. 3 rules of accounting, Journal entry for cash sales and credit sales. 2. What is purchase order and Ordering document? 3. What is Vlookup in excel, how and when do you use that? 4. Interviewer asked me to write an mail to client in two minutes. the situation was "The client has missed to submit an important document, how would you write this in the mail?"