Here are the completed sentences using the comparative form of the adverbs derived from the corresponding adjectives:

1. It usually rains **more heavily** in Central Vietnam than in other regions.
2. I will have to try a bit **harder** than this.
3. The hall was lighted **more brightly** than the corridors.
4. Time goes by **more quickly** when we are busy.
5. Our family has lived **happier** in the country than in the town since last year.
6. The boys were playing the game **more noisily** than the girls.
7. This task can be completed **more easily** than a buffalo or a horse.

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