完成句子。
1. — Are you still thinking about yesterday's game?
— Oh, that's _____ (让我激动的事).
2. I wonder _____ (我们能做点什么) about it.
3. _____ (他不能明白的是) was why fewer and fewer students showed interest in his lessons.
4. Mary wrote an article on _____ (为什么这个队没赢得比赛).
5. The problem is _____ (谁要来帮助我们).
