Which statement best expresses the main idea?

Moving the furnaces to one island protected the city and also concentrated a valuable craft (The passage gives the fire reason, then the 'second effect' of keeping skill and secrecy in one place, and finally the results of that concentration.)

What was the official reason for moving the furnaces to Murano?

the risk of fire in a city built of wood ('The official reason was fire', explained by the wooden piles and crowded workshops.)

The passage suggests that the Republic restricted the masters' travel because

it wanted to keep their methods from spreading to other countries (The paragraph links the island to knowledge staying in one place, then lists rewards for staying and punishments for leaving. The point is control of the technique.)

In this passage, 'tint' means

a faint colour in something (The workshops burned away the 'green tint' to make glass 'clear, colourless', so a tint is a light shade of colour.)

The Island Of Glass: Level 3 Reading Comprehension Questions

In 1291 the rulers of Venice ordered every glass furnace in the city moved to Murano, an island in the lagoon. The official reason was fire. Venice stood on wooden piles, its workshops were packed close together, and a furnace burning day and night was a danger to everything around it.

The move had a second effect, whether or not anyone planned it. Once the glassmakers all lived on one small island, their knowledge stayed there. Masters gained real status; they were allowed to wear fine clothes, and their daughters could marry into noble families. They were also forbidden to leave. A master who set up a furnace abroad could lose his family's protection at home, and agents of the Republic were sent to bring him back.

Behind that quiet border the craft advanced quickly. Murano workshops learned to burn away the green tint of ordinary glass and produced a clear, colourless glass they called cristallo, thin enough to bend light like rock crystal. Mirrors, lenses and drinking glasses from the island sold across Europe for centuries. The secrets did leak in the end, as secrets do, but by then Murano's name was itself the product.

Comprehension questions