According to the passage, iron was NOT used for beams, columns, and girders prior to the early eighteenth century because _____. A. all available iron was needed for other purposes B. limit

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According to the passage, iron was NOT used for beams, columns, and girders prior to the early eighteenth century because _____.

all available iron was needed for other purposes

limited mining capability made iron too expensive

iron was considered too valuable for use in public buildings

the use of charcoal for refining ore produced poor quality iron

Giải thích

Đáp án D

the use of charcoal for refining ore produced poor quality iron

Thông tin nằm ở đoạn 1: “…instead of charcoal for refining iron ore. Previously the poor quality of the iron had restricted its use in architecture…”

Theo đoạn văn, sắt đã không được sử dụng cho xà, cột và dầm trước khi đến đầu thế kỷ 18 bởi việc sử dụng than củi để luyện quặng tạo ra sắt chất lượng kém.