同学你好，该知识点来自沪江网校《【Uni智能】大学英语四级高效备考班》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学好！
made of wood and bamboo作为一个插入语，修饰kite. 当然，同学说的非限定性定语从句也可，变为：It is said that his kite, which is made of wood and bamboo
但由于这句话比较长，直接用插入语修饰，比用一个定语从句简便一些~

be made of 表示“由...制成”，制成以后还看得出原材料。
This table is made of wood.
这张桌子是由木头做成的。

be made in指的是产地，意思为于…制造。
The caps are made in Russia.这些帽子产于俄罗斯。。

祝学习愉快！