Five Definitions of Deep Structure

1. Deep structure is the output of phrase structure rules
   We can not have deep structure if we don’t have phrase structure rules.

e.g.

2. Deep structure is the input of transformation rules. We can apply transformation rules if we have deep   structure.

3. Deep structure is the level of grammar which can explain adequately the concepts of subject, direct object and indirect object.

• Subject is a noun phrase which is directly dominated by category of sentence.
• Direct object is a noun phrase which is directly dominated by verb phrase
• Indirect object is a noun phrase which is directly dominated by prepositional phrase.

e.g.

4. Deep structure is the level where we can apply selectional restriction rules (rules that restrict the selection of lexicons in a sentence)

e.g. the grass devoured the elephant (it is impossible, how the grass can eat an elephant)

The rule is:

- animate + animate > subject

+ animate +animate < subject

e.g. The tiger devoured the goat. 

The ones who don’t follow the selectional restriction rules are the linguist, writers, author.

5. Deep structure is the level which can solve the problem of ambiguity.

e.g.
"The girl hits the man with an umbrella."

Tree diagram

Note:

• The meaning: the girl hits the man who brings an umbrella;
• The PP is directly dominated by NP.

Note:

• The meaning: the girl hits the man by using an umbrella;
• The PP is directly dominated by VP.

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See also:
Chomsky's Generative Linguistics: An Introduction
Linguistic Competence and Linguistic Performance
Deep Structure vs. Surface Structure
5 Definitions of Deep Structure
Phrase Structure Rules
Transformation Rules

Tree Diagram