1. What kind of idea did the students think of to express their thanks to their teacher?
They thought of an idea of having a farewell party for Mr Thomas to surprise him.
2. What do you usually do to express your gratitude to your teacher?
I usually express my gratitude to my teacher by saying "thank you" after class, writing a thank-you card, or helping the teacher with some class-related tasks. (这个答案是开放性的，可以根据个人实际情况来回答。)
答案：【解析】：
1. 第一题是阅读理解题，需要从文本中找到学生们为了向老师表达感谢而想出的办法。根据文本，“they thought of an idea of having a farewell party for Mr Thomas to surprise him.”这句话直接给出了答案，即学生们想出了为Mr Thomas举办一个告别会来给他惊喜的办法。
2. 第二题是开放性问题，询问学生通常如何向老师表达感谢。这个问题没有固定答案，可以根据个人实际情况来回答。
【答案】：
1. They thought of an idea of having a farewell party for Mr Thomas to surprise him.
2. I usually express my gratitude to my teacher by saying "thank you" after class, writing a thank-you card, or helping the teacher with some class-related tasks. (这个答案是开放性的，可以根据个人实际情况来回答。)
