1) Were to the History of Construction With the introduction of the railways and steam machinery, transportation and manufacturing costs considerably reduced and concrete came to be more widely used, but it was still very much a neglected materia? - общий 2) The big break-through was the discovery of Portland cement by Joseph Aspdin in 1824, a worker in an English town, wasn't it? - разделительный 3) What was first used on a large scale in the construction of the Thames tunnel in 1828? - специальный к подлежащему 4) Were patents taken out for all sorts of systems in all countries or cities? - альтернативный 5) When has the post-war era given the biggest boost to concrete, both reinforced and prestressed? - специальный
