…………… wells are very deep.

Answer

**Step-by-Step Solution:**

1. **Understanding the Types of Wells**: There are two main types of wells: open wells and tube wells.
- Open wells have a larger diameter and are generally shallower.
- Tube wells have a smaller diameter and are designed to be much deeper.

2. **Characteristics of Open Wells**:
- Open wells have a wide opening and are usually not very deep.
- They are often used for domestic purposes and can be found in many rural areas.

3. **Characteristics of Tube Wells**:
- Tube wells have a narrow diameter and are drilled deep into the ground.
- They are specifically designed to access deeper groundwater sources.

4. **Conclusion**: Based on the characteristics of both types of wells, the answer to the question "…………… wells are very deep" is that **tube wells are very deep**.

**Final Answer**: Tube wells are very deep.

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