Deep structure and surface structure

Okay, let's imagine you're playing with some building blocks. You can stack them up in many different ways to create different structures. Just like building blocks, words in a sentence can also be arranged in different ways to create different meanings.

When we talk about deep structure and surface structure, we're talking about the different ways that a sentence can be built using the same words. The deep structure is the sentence's underlying meaning or the idea it's trying to convey. Surface structure is the way the sentence is actually written - the order of the words and how they're put together.

Let's use a simple sentence as an example to understand this better:

"The boy hit the ball."

This is the surface structure of the sentence. The words are arranged in a very straightforward way. But we can change the sentence's deep structure by using different kinds of phrases, like prepositional phrases, to add more information or change the order of the words. Here are some examples:

- "The ball was hit by the boy." (passive voice)
- "The boy who wore a red hat hit the ball." (using a relative clause)
- "After eating his lunch, the boy hit the ball." (using a prepositional phrase)

In each of these sentences, the words are arranged differently, but they still convey the same basic idea - that a boy hit a ball. So the deep structure remains the same, but the surface structure has changed.

Overall, deep structure and surface structure relate to how we understand sentences and how they can be changed to convey different meanings. The deep structure is the core meaning behind a sentence, while the surface structure is the way the sentence is actually written.