题目内容：

阅读下列材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

Plastic is a huge problem for our planet. It is really 1. (challenge) to get rid of and a lot of it ends up in nature or in the ocean in particular. There, it is a threat 2. our animals and plants.

Now a company from the Netherlands, a small country in western Europe, says that it will use plastic 3. (find) in the ocean to build roads. Volker Wessels 4. (turn) the plastic into building blocks for the roads. They will be like puzzle pieces 5. fit into each other.

Not only will this be good for the environment, but also it will be good for the people who look after roads. If a part of the road 6. (damage), it will be easy to remove it and replace it with another piece. The company says that nearly any type of plastic can be used 7. (make) the road pieces.

Scientists 8. (work) on the project say that they are in the final stages of testing the materials for 9. (safe). They say that the first road built will be 10. bicycle path somewhere in the Netherlands.