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Recent studies have shown that air into a hous
问题详情
Recent studies have shown that air into a house often has higher concentrations of contaminants than heavily polluted air outside.此题为多项选择题。请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：into—in
考查介词。into表示动作的方向，此处表示所处位置应当用介词in。
