Решение:
Расставляем предложения в правильном порядке, чтобы получилась история:
- At the beginning of the semester, Nigina decided to take part in a science club.
- During the first meetings, she mostly listened and observed others.
- Gradually, she began to share her ideas and ask questions.
- By the end of the semester, she had become an active member of the club.
Ответ: 2, 4, 3, 1.