Try the gap-fill exercise below the following passage. It's the same passage that we saw in last week's lesson.
A Work of Genius
By the beginning of the 15th century, after a hundred years of construction, Florence Cathedral was still missing its dome. The building required an octagonal dome which would be higher and wider than any that had ever been built, with no external buttresses to keep it from spreading and falling under its own weight.
The building of such a masonry dome posed many technical problems. Filippo Brunelleschi, who is now seen as a key figure in architecture and perhaps the first modern engineer, looked to the great dome of the Pantheon in Rome for solutions. The dome of the Pantheon is a single shell of concrete, the formula for which had long since been forgotten. Soil filled with silver coins had held the Pantheon dome aloft while its concrete set. This could not be the solution in the case of the Florence Cathedral dome, due to its size. Another possible solution, the use of scaffolding, was also impractical because there was not enough timber in the whole of the region of Tuscany.
Brunelleschi would have to build the dome out of brick, due to its light weight compared to stone and being easier to form, and with nothing under it during construction. His eventual success can be attributed, in no small degree, to his technical and mathematical genius. Brunelleschi used more than four million bricks to create what is still the largest masonry dome in the world.
Fill each gap in the summary with a letter A - I.
Due to the 1)______ and 2)______ of the required structure, the construction of a dome for the cathedral in Florence had challenged architects for many years. A method employed by the Romans, using 3)______ to support a dome while it was being built, was not suitable, and an insufficient supply of 4)______ meant that scaffolding could not be used either. The architect Brunelleschi finally 5)______ in building the largest 6)______ dome in the world.