29. (a) Although color is (b) a minor factor in soil composition, it (c) is excellent characteristic by which to distinguish (d) different soil layers.
정답은 (c)라는데 어떻게 고쳐야 할까요?
39. Maryland, (a) even though a southern state, (b) remained (c) loyalty to the Union (d) during the Civil War.
정답은 (a)입니다만, (a) 도 이상하지 않나요? even though 접속사 아닌가요(주어 + 동사 절이 와야 하지 않나요)