I'm trying to prepare for my final exam in syntax and have a few questions while reflecting on previous work. I'm not sure what is meant when asking which is immediately contained.
Immediately contained = there are no nodes in between, e.g. in the (sub)tree
DP are immediately contained in
D is not (because the node
DP is standing between
NP are immediately contained in
N is not immediately contained in
DP, only mediately, because
NP is in between, and so on.
If you prefer kinship terminology, reword "X is contained in Y" as "X is a daughter or granddaughter or great grandaughter or great great ... granddaughter of Y", and "immediately contained" as "X is a daughter, but not a granddaughter or great great ... granddaughter of Y" (i.e. there are no other mothers in the family line between X and Y).
Containedness is a relative term, i.e. you must always specify in which node something is (immediately) contained; w.r.t. to a whole syntax tree this notion can't apply, so the question "Which nodes are immediatly contained in a syntactic tree" doesn't really make sense if you don't say what nodes they are supposed to be immediately contained in.