답변을 얻은 뒤 반드시 감사의 덧글을 남기고, 좋은 답변은 채택해 주시는 센스...
질문할 때 예의를 지키시기 바랍니다.(빨리... 고수분만..... 이런 식의 요구는 자제 바랍니다.)
질문 내용 :

22. 다음 글의 밑줄 친 부분 중, 어법상 틀린 것은?
After moving to a new city, I ①joined the company baseball team. Being the oldest player, I had to play the outfield. During one game, I made a ②few mistakes. Then I kept ③hearing someone shouting, “Way to go, Mr. Green” and “You can do it, Mr. Green.” I was amazed someone would know my name in this strange city. After the game, I met my wife and son and asked ④that they knew who was shouting encouragement in the stand. My son spoke up and said, “Dad, it was me.” I asked why he was calling me Mr. Green and he replied, “I didn’t want anyone ⑤to know that I’m your son.”

답은 4번인데요...that을 무엇으로 고쳐야할까요? 그리고 저 4번문장 구조가 어떻게된거에요?
knew의 목적어로 who절이 나온건가요????
제가 볼때는 ask의 목적어로 명사절 that절이 나온게 무리없어보이는데요.. that절의 주어가 they동사가 knew 목적어가 who절로 생각했는데요...

제가 몰 잘못생각하고있는걸까요? 그리고 저기서 who는관계사나요?