You are a helpful assistant that breaks down a complex user request into a series of simpler, sequential utterances that sound natural.

**Your Task:**
Write a natural language user utterance for each group of tools.
- The first utterance should state the initial part of the goal.
- Subsequent utterances should sound like a user continuing the conversation after a previous step was completed.
- Each utterance should correspond to the tools in its group.
- If there is only one sub-task, the user utterance should reflect the same and should not sound like it is part of a sequence. For example, do not use "First,.." or similar phrases in such cases.
- These utterances must sound like they are directed by a user to a digital assistant or chatbot.
- NEVER provide any actual values for any parameters in any form.

Return your response ONLY as a JSON array of strings. The number of strings in the array must be exactly same as the number of tool groups.

---

**Example 1:**

**Overall User Goal:**
Find a flight and a hotel for my upcoming business trip, and book them if they fit my schedule.

**Tool Groups:**
- Tools for sub-task 1:
  - find_flights: Find available flights for the trip.
  - find_hotels: Find available hotels for the trip.
- Tools for sub-task 2: 
  - check_calendar: Check the user's calendar for conflicts.
- Tools for sub-task 3: 
  - book_flight: Book the selected flight.
  - book_hotel: Book the selected hotel.

**Expected JSON Output:**
[
  "Can you find me some flight and hotel options for my upcoming business trip?",
  "Okay, those look good. Before we book, can you just double-check my calendar to make sure there are no conflicts?",
  "Everything looks clear. Please go ahead and book that flight and hotel for me."
]

**Example 2:**

**Overall User Goal:**
Schedule a one-hour team meeting next week at a time when everyone is available.

**Tool Groups:**
- Tools for sub-task 1:
  - find_available_times: Find times when all attendees are free.
  - schedule_meeting: Schedule the meeting at the selected time.

**Expected JSON Output:**
[
  "Please find a one-hour slot next week when all my team members are available and schedule the meeting."
]

---

Now, generate the user utterances based on the provided overall goal and tool groups. The number of utterances should match the number of tool groups ({num_groups} in this case).

**Overall User Goal:**
{high_level_goal}

**Tool Groups:**
{tools_str}

**JSON Output:**
