The word for " is " is either " ∅, " or " -DIr " which are suffixes and taught in next two lesson " To Be "
The first difference is that "o" is a bit crazy, so it can mean "he/she/it/that". The word "that", however, could also be "şu" in Turkish.
If we're translating the word "that" on Duo, you can usually take your pick (o/şu) because English only has one word. But Turkish has two words based on distance:
- şu = that (closer)
- o = that (further away- possibly out of sight)
It's not an exact science, so the actual distance can vary greatly in each situation, but let's use a shop as a common example. You could ask the price for:
- bu = "this" near you
- şu = "that" near the shop keeper
- o = "that" on the other side of the room, far from both of you
If there is only one "that" (like your examples: "o/şu bir örümcek"), there is no difference in meaning between "şu" and "o"... except that "o" has multiple personalities, so it can also mean "he/she/it". I hope that helps. :-)