누가 이런걸 물어보더라구요

저도 답을 찾다보니  정말 햇갈립니다  제가생각한 답이랑  진짜 답이 틀리네요

누가 설명좀 해주세요

명사절 what 이랑  관계대명사 which , who , whom, that 구분하는건 좀 알겠는데요

앞에 선행사가 있느냐 없느냐의 차이니까요 그런데

명사절 what 이랑  의문사절(의문대명사) what, which 구분하는게 헷갈리네요

1번 문제도  명사절과  관계대명사절 구분을 묻는건 아닌듯해서요~

2번 문제는 of 전치사 뒤에 명사절 what 이 온것이 선행사가 없어서 입니까?

3번 문제는  against 전치사 뒤에 오는 명사절이라서 what이 오는거 맞죠? which는 선행사가 필요하니까
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1.
The witness claimed to be unable to recall __________ he had said about the matter.
A. which
B. what
 
답은 which랍니다.
왜 what은 안 되옵니까.
 
2.
This experience allows Carldinx Systems to have the best possible understanding of _______ our customers expect from our various card programs.
A. which
B. what
 
답은 what이랍니다.
왜 which는 안 되옵니까.
 
3.
Efficiency enters the picture when the resources demanded to achieve an objective are weighed against _________ was actually accomplished.
A. which
B. what
 
답은 what이랍니다.
왜 which는 안 되옵니까.

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