1-C. Wood used to be used as the main fuel, but nowadays fossil fuels are used widely.Wood used to be used as the main fuel, but nowadays fossil fuels are used widely.
2-C. An interesting exception is Japan, as its language is not widely used overseas.An interesting exception is Japan, as its language is not widely used overseas.
興味深い例外は、日本です、というのも、その言語は、広く使用されていないので、海外でダヨ。
3-C. This is why countries where instruction is offered in widely used languages (e.g. English, French, and German) are popular destinations for foreign students.This is why countries where instruction is offered in widely used languages (e.g. English, French, and German) are popular destinations for foreign students.
4-C. It was not until the latter half of the 19th century that they became widely popular.It was not until the latter half of the 19th century that they became widely popular.
次が、ありませんでした、後半までダヨ、19世紀のダヨ、それらが広く普及するようになったことがダヨ。
5-C. In modern society, dance is widely recognized as a form of entertainment: many people enjoy dancing for fun or watching their favorite artists dance on stage or screen.In modern society, dance is widely recognized as a form of entertainment: many people enjoy dancing for fun or watching their favorite artists dance on stage or screen.