Bella: Sir, can you tell me the syllabus for the OHT's?? 
Michael: Prepare LTI systems and how to find stability related topics till lec 4
Bella: Sure sir, are you in your office??
Michael: Yes I am.. What do you need ??
Bella: I am facing a problem in finding stability of a system.. 
Michael: Yeah sure .. you can come to my office .. 
Bella: i will reach in 5 minutes..
Michael: i am waiting
Michael gives Bella the syllabus for the OHTs. Bella has a problem with with finding stability of a system. Michael is in his office now. Bella will be there in 5 minutes.