문제 내용: 밑줄 친 부분에 들어갈 말로 가장 적절한 것은?
선택지 1: we can learn the Japanese language with extensive exposure.
선택지 2: duration is responsible for the robust results across studies.
선택지 3: it is impossible to register the stimuli at short durations.
선택지 4: people develop a liking towards stimuli that are familiar.