The fireworks were delighted the guests who were being seated along the riverside.

여기서

were delighted를 delighted로 바꿔야 한다는 건 알겠는데..

were being seated도 were seating나 seated로 바꿔야하지 않나요????????

불꽃놀이는 강변을 따라 '앉혀져 있던' 손님들을 기쁘게 했다. 이렇게 해석되는거 같은데...