| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | duct | United States | Ducts are commonly used for central heating and air conditioning systems in homes and buildings. | 1 |
| 2 | duct | United States | Ducts are commonly used for central heating and air conditioning systems in residential and commercial buildings. | 1 |
| 3 | duct | United States | Ducts are commonly used to distribute heated or cooled air throughout buildings. | 1 |