Grammar can be really, really hard.  Especially in English.  English has more exceptions than rules.  You do have to learn the rules.  You also have to learn the exceptions.  You also have to be ready for everything  to change.  And you can’t expect much help from teachers or textbooks.
Textbooks overemphasize the rules.  Teachers often tell you , “That’s how we say it.”  Trying to explain a rule and the exceptions gets too confusing, and in the end, it all boils down to: That’s how we say it.  But that may not be how you learn it.

How do you put those two together?  The rules and the exceptions?  Or in the fancy language of explanations Prescriptive vs Descriptive.​
It is more effective to find the rules yourself rather than trying to memorize them:  Making grammar.

Let’s start with the heart of it all.  We have words.  Grammar is the way we fit the words together to make sentences and express ideas.
There are three​ things we do as we fit the words together:
​ We change a word.                                                                  Dog bites man.                 Dog bit man.
We change​ the order of words.                                         Dog bites man.                 Man bites dog.
We add a new word.                                                                Dog bites man.           ​      Dog never bites man.

Each change also changes the meaning of the sentence.  The middle pair: “Dog bites man” and​​ “Man bites dog” is the classic example of what is and isn’t news.  A dog biting a man isn’t news, that’s normal.  A man biting a dog, that’s news because that’s very unusual.

Let’s look at another example.  See if you can explain how the grammar changes the meaning of the sentence, “I love you.”

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