it tjruned out that while they could hear high-pitched sounds easily, manatees had trouble
with the low-pitched sounds boats usally make.
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make 뒤에 목적어가 와야할 것 같은데, 목적어가 없어요.
그럼 앞에 목적격 관계대명사가 생략되어있는건가요 ?
친절하고 자세한 답변 부탁드리겠습니다.