3 The passengers (fell/falling) asleep one by one.
7 About half of the guests did not (bring/bringing) a wedding present.
9 Receiving news of an approaching war, the citizens (began/begun) to stock up on food.
위에 정답들이 왜 정답인지 이유좀 알려주세요ㅠㅠexercise는 풀이가 안나와있어서 왜 답인지 이유를 모르겠네요 부탁드려요ㅠㅠ