The word “They” refers to A. coal and wood B. main sources of fuel C. natural gas and oil D. industrializing countries
The word “They” refers to
A. coal and wood
B. main sources of fuel
C. natural gas and oil
D. industrializing countries
C
Từ “They” ám chỉ đến
A. than đá và gỗ
B. các nguồn nhiên liệu chính
C. khí tự nhiên và dầu
D. các nước công nghiệp hóa
Dẫn chứng: In 1910, natural gas and oil firmly replaced coal as the main source of fuel because they are lighter and, therefore, cheaper to transport. They burned more cleanly than coal and polluted less.
=>Chọn C