In the case of the bus, you could use either "this" or "that." The closer you are, the more likely you are to use "this," but it doesn't make much difference here. By the way, buses are always "it."hmm, okay... but how close?
Would you say: "Oh, look, this/that is the bus we have to take! We have to run to make him!" (You see the bus coming!)
and what about immaterial thing. You are discussing about something: "Yeah, I totally agree in this/that point!"
sry, I tried the search box... but it was too confusing or better didn't fit my question (sentences above) ... I am sorry...