1. It occurs between January twenty-first and February nineteenth. (sentence 3)

2. They tidy their houses, cook special food and make offerings... (sentence 5)

3. They sit up to the midnight to see the New Year Eve. (sentence 6)

4. Yes, they are. (sentence 7)

IV/

1. How long will they be in the town?

2. What was her father doing when the mailman came?

3. Andrew wants to win the first prize in the English-speaking contest, so he is training very hard now.

4. Mr. Green got up early so as to get to the meeting on time.

5. A new time machine will be made by Dr. Kim next year. (simple future passive)

6. Would you mind decorating the Christmas tree? (Would/ Do you mind + V-ing...?)

7. My brother has studied/ has been studying English since he was in grade 3.