A、The materials he used. B、His use of electric light. C、His use of geometric shapes. D、The number of windows. C细节题。文章提到，Kahn的作品的

Louis Kahn helped define modern architecture. Kahn’s architecture has several defining qualities. Kahn was very interested in the look and feel of the materials he used. He used brick and concrete in new and special ways. Kahn also paid careful attention to the use of sunlight. He liked natural light to enter his buildings through interesting kinds of windows and openings.[26]Kahn’s work can also be identified by his creative use of geometric shapes. Many of his buildings use squares, circles and three-sided shapes called triangles.
    Kahn’s first projects involved building housing in Philadelphia. In 1942, he became a head architect of the Public Building Administration.[27]Kahn’s first important project was the Yale Art Gallery in New Haven, Connecticut in the early 1950s. This building was very popular. Its completion represented an important step in Kahn’s professional life. He was now a famous architect.
    Louis Kahn was an artist who created beautiful works. But he was not a very good businessman. He would change his designs many times. This would make each project take a great deal of time and cost more money. The majority of the projects he designed were never built. Also,[28]he did not like to compromise his design ideas to satisfy a buyer’s wishes. For this reason and others, Kahn did not make many buildings. His design company did not always have many jobs or much money. In fact, when Kahn died, he was in great debt. This is especially unusual since he was considered one of the most important architects in the world.
26. Which of the following is the creative feature of Louis Kahn’s architectures?
27. What made Louis Kahn become famous according to the passage?
28.Why didn’t Louis Kahn make many buildings?