It’s ten years since the scientist ___on his life’s work of discovering the valuable chemical.

After the long journey, the three of them went back home, _________.

_____ in the mountains for three days, the young man was finally saved by the local police [ ]

How is this kind of hamburger—It tastes ______ and sells ______.

You cannot be more careful when crossingthe street, or you may ___ by cars.