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질문 내용 : So when a grown man speaks to a girl in (which/what) he thinks is a normal voice, she may hear it as yelling.
위 문제에서 관대 앞에 선행사가 없으니까 what이 답이라고 하는데 그럼 아래 두문제도 모두 앞에 선행사가 없으니까 답은 what이라고 해도 되는 건가요?

As the morning fog lifted, the sharp peaks of the Hohe Tauern mountain range slowly emerged, some of ( which/what)were very much alive.

Unlike a serious hangover, to (which/what) researchers have compared CFS, the profound weakness of CFS does not go away with a few good nights of sleep.