Final answer:
In the grammar provided by the student, sentences produced will either have a symmetrical pattern of 'a's and 'b's or start with a sequence of 'c's followed by a mixture of 'y's or 'z's, or potentially end immediately after the 'c's.
Step-by-step explanation:
The general form or shape of all sentences produced by the given grammar will adhere to a specific pattern. Starting from the initial symbol S, there are two distinct paths to generate sentences. One path follows the production S → a S b b, creating sentences that begin with an 'a', followed by any sentence that the grammar can produce, and then ending with two 'b's. This recursive pattern will result in sentences that have a number of 'a' symbols equal to the number of 'b' symbols multiplied by two, maintaining a 'a' (1) to 'b' (2) ratio, always beginning with 'a' and ending with 'b b'. The second path uses the productions X → c X | c Y and Y → y Y | z Y | ε, which builds strings starting with a sequence of 'c's followed by a combination of 'y's and 'z's, or ending immediately after the 'c's if epsilon is chosen. Therefore, these sentences will always start with one or more 'c's. When the epsilon is not chosen, it follows with a string containing only 'y's and 'z's, ending with either 'y' or 'z', or it may be empty if it is terminated with the epsilon right away.