1. **Is the object a long cylinder?**
   - **Answer:** Yes
   - **Reasoning:** All three images show an object with a cylindrical shape that is elongated, characteristic of what is typically described as a "long cylinder."

2. **Is the cylinder hollow?**
   - **Answer:** Yes
   - **Reasoning:** The images clearly depict a cylindrical object with a visible hole running through its length, indicating that it is hollow.

3. **Has the cylinder been extruded?**
   - **Answer:** Unclear
   - **Reasoning:** The images show a 3D model of a cylinder, but without specific information on the manufacturing process or the design method used (such as extrusion in CAD software or a physical manufacturing process), it is not possible to definitively say whether the cylinder has been extruded.

4. **Is there a semi-circular cut in the middle of the cylinder?**
   - **Answer:** No
   - **Reasoning:** None of the images show any visible cuts or indentations on the surface of the cylinder that resemble a semi-circular shape. The cylinder appears to be smooth and continuous along its surface.