[9급 국가직 영어 2024년 6번]

밑줄 친 부분 중 어법상 옳지 않은 것은?
Despite the belief that the quality of older houses is superior to ② those of modern houses, the foundations of most pre-20th-century houses are dramatically shallow ③ compared to today’s, and have only stood the test of time due to the flexibility of ④ their timber framework or the lime mortar between bricks and stones.
영어
정답 ②

출처: 인사혁신처 공개 기출(공공데이터포털, 이용허락 제한 없음)