آزمون آنلاین انگلیسی 3 - درس سوم | آزمون شماره 367

According to the scientific reports , ........................... energy sources such as solar power and wind power offer clean energy that is both safe for our environment and good for the  economy. economy

.One major pollution problem is that governments don't know what to do with the .................................  produced by nuclear power plants

.................................... of living in big cities force everyone to move there despite its problems.