아이가 고3인데 중간고사에서 다음과 같은 문제가 출제되었습니다.
수능특강 지문에서 문법 문제를 낸 것인데요.
8. (a), (b), (c)에서 어법에 맞는 표현으로 가장 적절한 것은?(3.3점)
wood is (a) what / that is widely acknowledged to be environmentally friendly. it has been welcome as an alternative material for a long time in building houses instead of cement or bricks. however, it is not always easy to evaluate the relative merits of one particular material such as wood over another. many species of tree now endangered, including mahogany and teak, and deforestation, particularly in tropical rainforests, (b) has / have had a severe impact both on local communities and on indigenous plants and wildlife. where wood is harvested, then transported halfway across the globe, the associated energy costs are high, (c) causing / caused a negative impact on the environment. what is more, where wood is treated with chemicals to improve fire- and pest-resistance, its healthful properties are compromised.

수능특강에 나오는 원문은 이렇습니다.
수능특강 3강 3. 목재 이용 시 환경에 미치는 부정적 영향
wood is a material that is widely acknowledged to be environmentally friendly. it has been welcome as an alternative material for a long time in building houses instead of cement or bricks. however, it is not always easy to evaluate the relative merits of one particular material such as wood over another. many species of tree are now endangered, including mahogany and teak, and deforestation, particularly in tropical rainforests, has had a severe impact both on local communities and on indigenous plants and wildlife. where wood is harvested, then transported halfway across the globe, the associated energy costs are high, causing a negative impact on the environment. what is more, where wood is treated with chemicals to improve fire- and pest-resistance, its healthful properties are compromised.정답은 (a) what / (b) have / (c) causing 이라고 합니다.
(b)의 경우 many species of tree now endangered가deforestation, particularly in tropical rainforests와 함께 주어가 되어서 동사가 have가 되어야 한다는 것인데요.아이는many species of tree now endangered가 의미상으로 문장의 뒷 부분에 나오는a severe impactboth on local communities and on indigenous plants and wildlife의 주어가 될 수 없는 것이므로deforestation, particularly in tropical rainforests만이 주어라고 생각해서 답을 has라고 하였답니다.
많은 아이들이 그렇게 답을 하였다 하는데요.
출제 선생님에게 이의 제기를 하여도 명확한 답변 없이 묵살하였다 하네요.
수능특강 원문을 변형하여 출제하는 과정에서 선생님이 잘못한 것 같은데, 아이 선에서는 더이상의 이의제기가 불가능한 상황이라 학부모인 제가 나서보려고 하는데요.
이 한 문제로 인하여 등급이 갈리고 있어서 중요한 한 문제랍니다.선생님에게 has도 정답으로 처리해 달라고 요구하여도 좋을지 여러분들의 의견을 듣고 싶습니다.
그냥 지나치지 마시고 의견 올려주시면 대단히 고맙겠습니다~감사합니다~