Work in pairs.match the words with their definition : 1.concrete 2.stairs 3.clay 4.brick 5.landing 6.railing 7.staircase 8.to whitewash a.type of earth that is soft when it is wet and hard when it is dry b.to paint walls white with a mixture of chalk and water c.blocks of baked clay that are used for building walls d.a substance ased for building and made from cement , sand , small stones and water e.balustrade f.a set of steps inside a building g.a set of stairs inside a building h.an area at the top of a staircase , with rooms leading off it