请各位大虾帮忙看下我翻译的一个句子对不对，如果不对应如何修改(定语从句），万分感谢了！！！！

不对

这是一个考验真题作文吧，参考如下

Two tourists sitting in a boat are throwing garbage into the lake which is already filled with various wastes.

百度教育团队【海纳百川团】为您解答

among：不一定是“正中央”的意思。
建议：
两名游客在船上坐下后，就开始往湖里扔垃圾了，而湖里已经堆积了各种各样的垃圾。

可以更简洁一些：两个坐在船里的游客正往满是垃圾的湖里倒垃圾。

　　The two tourists seated on the boat is littering rubbish into the lake, while there is much more of all kind floating in it. 简洁版
　　The two tourists who are seated on the boat is littering rubbish into the lake, while there is much more rubbish which is of all kind floating in it. 定语从句

Two tourists sitting in the boat are going full of garbage lake trash