1. The twins probably watched the other children play 'through their sad dark eyes' because they were unable to join them for some unknown reason. Their eyes looked sad because the twins probably felt sorry for themselves.
2. The author was upset the evening she saw Nieves walking behind her she thought that Nieves was mad and that he was stalking her with the intent of harming her.
3. The author's mother probably felt both relieved and embarrassed when she realized why her child was upset. On the one hand she felt relieved because she realized that the apparent danger that her daughter was running from was not a real danger. On the other hand, she felt embarrassed because her daughter had misjudged the man who was going to work with her husband.
4. The townspeople probably just got accustomed to Nieves and learned to ignore his peculiar behavior after realizing that he hadn't done anything harmful to anyone over the course of his stay in the town.
