Sure! Here’s a breakdown of the dialogue with explanations for the choices:

### 1. Tom: Let’s go to the zoo tomorrow.
**Mary:**
**A. Good idea.**
**B. I’d love to.**
**C. I don’t think so.**

**Chosen response:** **A. Good idea.**
**Reason:** This option conveys enthusiasm and agreement with Tom's suggestion.

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### 2. Tom: She’s tall and slim.
**Mary:**
**A. What does Helen look like?**
**B. What is Helen like?**
**C. Who is Helen?**

**Chosen response:** **A. What does Helen look like?**
**Reason:** This question is relevant as it seeks to clarify Helen’s physical appearance, which fits the context.

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### 3. Tom: Would you like to join our trip?
**Mary:**
**A. Yes, let’s.**
**B. I promise.**
**C. Great! I’d love to.**

**Chosen response:** **C. Great! I’d love to.**
**Reason:** This response is enthusiastic and expresses a strong desire to join the trip.

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### 4. Tom: She’s friendly and helpful.
**Mary:**
**A. What does Helen look like?**
**B. What is Helen like?**
**C. What does Helen like?**

**Chosen response:** **B. What is Helen like?**
**Reason:** This question asks about Helen's personality, which is relevant to the statements Tom made.

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### 5. Tom: I think pop music is interesting.
**Mary:**
**A. I agree.**
**B. So am I.**
**C. OK.**

**Chosen response:** **A. I agree.**
**Reason:** This response shows agreement with Tom's opinion on pop music.

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Feel free to ask if you need more help!