The certified flight instructor (CFI) of a Schweizer SGS2-33A glider stated that the accident flight was his first training flight with the student. He reviewed the student's logbook and ascertained that he had a total of 25 flight hours in gliders. The CFI gave the student pilot ground instructions regarding speed limitations, pattern and approach speeds, and pattern entry execution. The student then performed the launch and tow to 2,500 feet above ground level, and the in-flight maneuvers were uneventful. During the approach to land, the CFI instructed the student pilot to "make a shallow left turn to get closer to runway 23;" however, the student pilot turned right. The CFI repeated "turn left," but the student pilot again turned right. The CFI advised the student pilot that he was taking control of the glider. He said that he repeated this to the student pilot but he did not respond nor did he relinquish control of the glider. Consequently, the glider impacted nose first into the ground. Examination of the glider by a Federal Aviation Administration inspector revealed that the wings and fuselage were buckled.