(1) __C_____, people relied on iceboxes to keep food cold. These were insulated wooden boxes lined with zinc or tin. Large blocks of ice, harvested from frozen lakes or rivers in the winter, were placed inside a compartment at the top. (2) __A__, keeping the food below cool.
Iceboxes were a vast improvement over simply leaving food at room temperature, but they weren't perfect. The ice needed to be replaced regularly, often every few days, (3) __D___. Additionally, the coldest area was near the bottom, so people had to be careful about where they stored different foods. Milk, for example, spoiled quickly if not kept very cold.
Despite their limitations, iceboxes were a vital tool for food preservation for many years. They allowed families to store leftovers, (4) ___B__, and even enjoy a refreshing cold drink on a hot summer day.
A. The cold air from the melting ice would slowly travel down
B. keep dairy products fresh for longer
C. Before refrigerators became commonplace in the early 20th century
D. which could be inconvenient and expensive
