But before refrigeration, it was 25_____ (considered, thought, judged, believed) a luxury. For many years, people 26 ______(produced, did, made, created) ice cream only by hand. The key ingredients – milk and sugar, cream and eggs – were 27 ______(filed, located, laid, placed) in a bowl that was then put in a larger container with salt and ice.
Then the ingredients had to 28 ______(remain, stay, have, be) churned (or stirred). Before refrigeration, ice had to be cut from lakes and ponds and 29 ______(stored, saved, collected, gathered) in the ground. Ice harvesting was a very profitable business in areas that had a lot of ice. Merchants shipped ice all around the world. In 1926, the modern freezer was 30 ______, and the mass production of ice cream became possible.​