Question

Now that you have worked through a lot of material that includes these basic patterns, and you have compared grammatically correct and incorrect sentences, write down what you think is a rule that could explain what makes a sentence grammatically correct or not. For example, you might write something like: "verbs always match nouns in number, and they usually come before the noun." In other words, make your best guess for the grammar rule that makes sense out of the pattern(s) you see in the phrases you have been working with. Review if you need to, and you might briefly check your hunches against the sentences you have been working with in this or previous modules. Keep in mind that what you're after is your hunch, not a grammar rule from a text book. Now check your hunch with the explanation of this principle in the following pattern.

Answer 1

Here’s a simple hunch that tries to capture what makes a sentence “grammatical” (your hunch, not a textbook definition):

- A sentence is grammatical when each word is in the position and form that the verb and other words expect: subjects and verbs agree in person/number, words appear in the correct order for the language, and verbs take the complements they require. In short: each word must “fit” the syntactic slots and match the required features of the words that govern them.

Now check that hunch against the core principle behind the patterns you’ve been seeing — broken into three easy parts:

1) Agreement (matching features)
- Principle: Subjects and verbs (and sometimes other words) carry features like person, number, and tense; those features must line up where the grammar requires.
- Example: Correct: “She walks.” Incorrect: “*She walk.”
Why: “She” is third person singular, so the verb needs the matching 3sg form.

2) Word order (position matters)
- Principle: English uses a fairly fixed word order (Subject–Verb–Object). Putting words in the wrong order usually breaks meaning or makes the sentence ungrammatical.
- Example: Correct: “The dog chased the cat.” Incorrect: “*Chased the dog the cat.”
Why: The verb must follow its subject and precede its object in normal English declaratives.

3) Subcategorization/valency (complements the verb requires)
- Principle: Some verbs require particular complements (an object, a location phrase, etc.). If those complements are missing or the wrong type, the sentence will be odd or ungrammatical.
- Example: Correct: “She put the book on the shelf.” Incorrect: “*She put the book.”
Why: “put” requires both an object and a location/result phrase; without the location the verb’s requirements are unmet.

Other common constraints that fit the hunch
- Determiners and countability: Singular English count nouns typically need a determiner: Correct: “The dog barked.” Odd or infelicitous: “*Dog barked” (in ordinary contexts).
- Tense: Verb form must match the time reference: Correct: “Yesterday he went.” Incorrect: “*Yesterday he go.”

Summary
- Your hunch — that grammaticality comes from words matching the requirements and positions imposed by other words (agreement, order, required complements) — is a good practical rule of thumb. Most ungrammatical sentences you’ve seen violate one of those conditions: wrong agreement, wrong word order, or a verb’s complement requirement not being satisfied.