So, ________ the government has a good system of control or can educate the people, the forests will slowly disappear.
The astronauts found that ______ the spaceship went further and further into space, it became more and more difficult to control its own movements.
What he said suggested he ______ angry with us so I suggest you ______ an apology to him.
Have you ever been to Mount Huangshan, ___________is famous for its pine forests and "sea of clouds"?
writing the article, Mrs. Curie even forgot her dinner.
While riding in the street, _____________.