' To the point' answers in just 5 6 lines.

Q1. A context dependent programming language is one whose keywords and other symbols are not fixed in meaning or grammatical usage but depend on the context. This enables you to create 'dialects' of the language which can form the basis of 'domain specific languages'. An example of a context dependent programming language is REBOL.

Q2. Languages which lack control structures need to use GOTO (or a similar keyword) in combination with labels (or line numbers) to control the flow of execution of a program. This can lead to 'spaghetti code' which has an adverse effect on readability.

Q3. The inability of a C function to return an array is connected to the fact that you can't assign an existing array to an array variable - you can only declare or initialize the latter. This is because an array variable contains a constant pointer to the first element of the array and so can't be changed to point to a different array. Consequently, there would be no point in functions returning an array as the return value couldn't be assigned to an array variable. This restriction doesn't apply to structs.