1-C. The British government failed to introduce a base-10 currency system.The British government failed to introduce a base-10 currency system.
英国政府は、失敗しました、10進法の通貨制度を導入することをダヨ。
2-C. 1971 was the first time that the British currency system changed.1971 was the first time that the British currency system changed.
1971年は、初回だった、というのは、英国の通貨制度が変更された(時制の一致)ダヨ。
3-C. In 1966, the government announced that the country would be switching to a base-10 system for their currency five years later.In 1966, the government announced that the country would be switching to a base-10 system for their currency five years later.
4-C. For example, Britain once used a complicated counting system for its currency units; 1 pound equaled 20 shillings, but 1 shilling equaled 12 pennies.For example, Britain once used a complicated counting system for its currency units; 1 pound equaled 20 shillings, but 1 shilling equaled 12 pennies.