Answer:
1. A: Look! My classmates Maria and Teresa!
B: (1) <u>Are</u> they Mexican?
A: No, they (2) <u>aren't</u>. They (3) <u>are</u> Peruvian.
2. A: That’s my friend Jerry.
B: (1) <u>Is</u> he a firefighter?
A: No, he (2) <u>isn't</u> . Barry (3) <u>is</u> a firefighter. Jerry (4) <u>is</u> a police officer.
3. A: (1) <u>Are</u> you a new student?
B: Yes, I (2) <u>am</u>. My name (3) <u>is</u> Brian.
A: (4) <u>Are</u> you from Australia? B: No, I (5) <u>'m not</u>. I (6) <u>'m</u> from the U.K.
Explanation:
In the Present Simple, the verb to be has three forms for the different subject pronouns:
I --> <em>am</em>
She / he / it --> <em>is</em>
We / you / they --> <em>are</em>
In that matter, the negative form of <em>am, is </em>and <em>are</em> are <em>am not </em>or <em>'m not, is not </em>or <em>isn't</em> and <em>are not</em> or<em> aren't</em>, respectively. Besides, in the interrogative form there is inversion of the verb <em>to be</em>, so that <em>am, is </em>and <em>are</em> are located before the subject.
