Questions 63 to 67 are based on the following passage: ( 10分 )　　Architecture is the art or science of designing and constructing buildings with durable materials following certain canons.　　Historically, architecture has followed a succession of recognizable styles that may, for example, be identified as Gothic, Baroque, or Neo-Classical; or it has a specific style associated with a particular culture, such as Greek, Roman, or Egyptian.　　Architectural style, even if it is a country house, factory, hotel, airport, or religious building, reflects the values as well as the needs of the society that produces it. However, it is governed not only by taste and aesthetic interest but also by many practical considerations.　　The availability of suitable materials is closely linked to the development of skills and influenced the shapes of buildings. Carpentry developed in areas of the world that were thickly forested. Although it has become scarcer, timber remains an important building material.　　In other areas, stone and marble were chosen for important monuments because they are fireproof and durable. Stone is also a sculptural material; stone architecture was often integral with stone sculpture. The use of stone has declined today because a number of other materials, such as glass, steel, and concrete are more economical to use and assemble.　　In regions where both timber and stone were scarce, earth itself was used as a building material. Mud or clay was compact into walls or made into bricks that were dried in the sun. Later, bricks were baked in kilns, which gave them greater durability.　　Building with stones or bricks is called masonry. The elements cohere through sheer gravity orthe use of mortar. The Romans found a natural cement that, combined with insert substances, produced concrete. In the early 19th century a truly waterproof cement, the key ingredient of modem cement, was developed. So, it is said that Romans are great contributor to the development of architecture.

In the architectural history, Romans

A．found a natural building material that can be used to produce concrete

B．were the first people who could produce concrete

C．found a truly waterproof cement

D．contributed most to the development of architecture