Not "I amn't ready." — say "I'm not ready.". I 的否定形式是 I'm not——没有 “amn't” 这种说法。
试一试: Lars says, "Hello, Amina!" Sofia says, "Sorry, ___ Amina. I'm Sofia." (I'm not / I isn't / I aren't) 答案: I'm not — I'm not Amina. I 的否定形式只有 I'm not，从来不是 isn't 或 aren't。
isn't
用 is 说“不”，就加上 not：isn't = is not。
He isn't here.
She isn't here.
It isn't here.
Not "He not is here." — say "He isn't here.". not 接在 is 后面 → isn't，不是放在它前面。
试一试: Sofia ___ here. (isn't / aren't / not is) 答案: isn't — Sofia isn't here. Sofia 是一个人（she），所以否定词是 isn't，不是 aren't。
aren't
用 are 说“不”，就加上 not：aren't = are not。You 永远用 are / aren't。
You aren't here.
We aren't here.
They aren't here.
Not "They isn't here." — say "They aren't here.". we, they 和 you → aren't，从来不用 isn't。
试一试: They ___ students. (aren't / isn't / not are) 答案: aren't — They aren't students. They 是不止一个人，所以否定词是 aren't，不是 isn't。
not 放在哪里？
not 放在 am / is / are 后面。
I am not ready.
She is not ready.
They are not ready.
Not "She not is ready." — say "She is not ready.". 先是 be 动词，再是 not。
试一试: We ___ ready. (aren't / isn't / not are) 答案: aren't — We aren't ready. We 是不止一个人 → aren't。not 接在 are 后面。
缩写形式：I'm, you're, he's, it's
isn't 和 aren't 是缩写形式。am、is 和 are 也有缩写形式：I am → I'm，you are → you're，he is → he's，it is → it's。撇号顶替的就是省掉的那个字母。
I'm Amina.
You're happy.
He's tired.
It's a book.
试一试: "Are you ready, Amina?" "Yes, ___ ready." (I'm / Im / I'am) 答案: I'm — I'm = I am。撇号顶替的是 am 里的那个 a。"Im" 漏了撇号，"I'am" 又把 am 整个留着，等于什么都没省。