however, because they had no person on whom to place their attention, they soon took on the appearance of extreme weariness; most students became lethargic and rested their heads on their desks.

제가 모르는 부분은 밑줄친 부분인데요, 관계대명사는접속사 역할도 하잖아요. 두문장이 어떻게 연결되어 있는지 설명해주시고,they had noperson whom to place their attention on. 이 문장에서목적격이니까 뒤에s+v가 나와야 하는데to부정사가 나올수 있는이유좀 설명해주세요 ^^