If I work hard at all my lessons from now on, will I do better in them—Sure, ____________________.

30. It was once called the Sea of Bamboo, but now only one fifth of the area ______ covered with bamboo, and sixty percent of other plants ______ taken the place of the bamboo.

I started off to walk, but Peter gave me a lift— Therefore, you _____ after all

In those days, we had no phones, so we have to keep in touch _________ writing often

In modern society, alternative energies __________traditional ones are playing an important role in our daily life. That’s justbecause scientists have made great breakthroughs _________ the development ofscience and technology.