21. (A), (B), (C)의 각 굵은 글씨 안에서 어법에 맞는 표현으로 가장 적절한 것은? While awaiting the birth of a new baby, North American parents typically furnish a room as the infant's sleeping quaters. For decades, child-rearing advice from experts has (A) encouraged / been encouraged the nighttime separation of baby from parent. For example, a study recommends that babi..