Bộ 20 đề luyện thi Chuyên Anh năm 2023 có đáp án (Đề 87)

As coal mines became deeper, the problems of draining water, bringing in fresh air, and to the surface increased. A. how ore is transported      B. transporting ore C. ore is transporting  

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As coal mines became deeper, the problems of draining water, bringing in fresh air, and ______ to the surface increased.

how ore is transported

transporting ore

ore is transporting

to transport ore

Giải thích

Đáp án: B