- 다음 중 어법상 틀린 것은?An increasing number of self-help groups have emerged in recent years. These voluntary groups ①in which people share a particular problem are often conducted without a professional therapist. During ②regularly scheduled meetings, members share their stories, stresses, feelings, issues, and recoveries. Information and knowledge are open and ③sharing rather than protected and controlled. They learn that they are not alone; they are not the only ④ones facing the problem. Self-help groups have been formed ⑤to deal with problems ranging from overeating and drug addiction, to child abuse, single parenting, adjusting to cancer, and gambling.

1번이 이해가 안되네요? 전치사+관계대명사...관계부사 형태라고 하는데
왜 그런지 설명해주세요? 그리고 전치사 in은 월래 위치는 어디인가요?
나머지도 자세한 설명해주시면 감사^^