1）翻译下面的句子：
约翰本来想找一个信封，但没想到读起了一些旧时的信件。
John was planning to find an envelope, but got sidetracked and ended up reading some old letters.
（参考翻译：John was looking for an envelope and got sidetracked reading some old letters.）
2）结合自己的生活、学习、工作、兴趣等，想象在什么语境下会用到这个表达。先简要描述这个场景，再造句。
场景 ：上课时学生让老师跑偏聊八卦
例子： The students sidetracked their teacher into talking about gossips in the entertainment industry.
