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질문 내용
1. that’s not easy, and the physical costs of producing a play, especially a musical, tend to eat up what money there is.여기서 what은 무슨 품사가 어떤 경위로 이렇게 쓰였는지요??
2. the cost of sets, costumes, and lighting, even when volunteers do the majority of the work, add up quickly.

여기서 주어가 cost 단수인데 왜 add 복수 동사가 나왔는지요?
3.
most toothpastes contain sls, or sodium lauryl sulfate which is used in many cleaning and hygiene products.
여기서 많은 세제에 sls가 사용된다는 의미인데, 왜 many를 썼으면서 cleaning에 --s를 안 붙였는지요?

4.
the day may come when that person is at the top, and you’re getting older and past your peak.

past는동사 품사가 아예 없다고 하는데, 그럼 여기서는older형용사와past형용사가 연결된 건가요??

꼭 답변 좀 부탁드릴께요!!!!

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