Building materials

> b) Give antonyms to the following words:
advantage disadvantage
softwoods hardwoods
fine aggregates coarse aggregates

c) Find in the text "Building Materials" adjectives in the superlative degree:
the oldest
the most important
the strongest

d) Give synonyms to the following words:
building materials structural materials
timber wood.
V. Listening. T: Listen to the text "Building Materials" (listen to the tape).
Building Materials
Steel, concrete, stone, timber and brick are the most commonly used building materials. Timber is the oldest structural material known to mankind. It is light, cheap and easy to work with. But timber has certain disadvantages: it burns and decays. Timber used for building purposes is divided into two groups: softwoods and hardwoods. Softwoods are chiefly used in construction, while hardwoods are generally used for decorative purposes.
Bricks were known many thousands of years ago. They are molded from clay into the required shape. Bricks are usually rectangular in shape. They are hardened by being fired in a kiln.
Concrete is one of the most important building materials. It is difficult to imagine modern structures without concrete. Concrete is made by mixing together a proportion of fine and coarse aggregates with cement and water. Crushed stone, broken brick and gravel, river sands are extensively used.
Reinforced concrete is a combination of two of the strongest structural materials available - concrete and steel. There are two kinds of reinforced concrete: with ordinary reinforcement and concrete with prestressed reinforcement. Concrete is reinforced by the incorporation of steel rods.
Plastics and glass reinforced pla