This description logic (DL) expression defines a "Question" using various properties. Let's break it down step by step in plain language:

- **∃has SPARQL query.∀has entity.∃thumbnail.⊤**  
  A question is related to a **SPARQL query**, which retrieves entities. For every entity it retrieves, there is a requirement for the presence of a **thumbnail** (an image or visual representation). The **⊤** symbol represents "anything," meaning there is some thumbnail, but no specific type is specified.

- **⊓ (intersection with)**  
  This means that the question must also satisfy the next condition.

- **∃has literal answer.⊤ ⊔ has IRI Answer. (Building ⊔ (∃see also.⊤⊓natural person))**  
  This part states that the question must either:
  - Have a **literal answer** (for example, a direct text-based or numerical answer), or
  - Have an **IRI answer**, which could refer to a linked entity (like a URL or a resource identifier). 
    - This linked entity can be either a **Building**, or
    - Something that is related to a **natural person** (a human being) and has some **see also** reference (meaning it is connected or linked to another relevant resource or concept).

### In Summary:
This DL expression describes a question that is tied to a SPARQL query that retrieves entities, each of which has a thumbnail. The answer to the question can be a literal value or an IRI (a resource), and this resource could either be a building or a natural person who is connected to other resources.