1. developing solar panels2. strong enough to stand up to heavy highway traffic3. making the roads more slippery4. making them relatively cheap and easy to install5. kick around the idea of paving its roads点击“下一章”,开启听写训练Day72~
1. developing solar panels
2. strong enough to stand up to heavy highway traffic
3. making the roads more slippery
4. making them relatively cheap and easy to install
5. kick around the idea of paving its roads