7.A
1. I have not seen him since last Christmas.
2. We have gone to Vung Tau several times.
3. He has already written to his parents.
4. Lien has not prepared her lessons yet.
5. They have just received a package from their grandfather.
6. Miss Huong has been teaching us English for 2 years.
7. My younger brother is studying his lesson at the moment.
8. We have never taken a bus to school before.
9. Next week, my uncle will come back home for Christmas.
10. When Peter was young, he liked to drink coffee.

7.B
1. Lan was my next door neighbor when I lived in Hai Phong.
2. They usually go fishing at weekends.
3. Mary made the dress for me a week ago.
4. At the moment, she is reading in the library.
5. Don't make noise. The baby is sleeping.
6. I have not finished the book yet.
7. Her mother gave her a new novel yesterday.
8. We often go skiing in winter.
9. When I was young, I usually played with a kite.
10. They have been building that building for two years.

7.C
1. The 22nd SEA Games took place in my country two years ago.
2. There has been no rain here for 6 months.
3. It is raining heavily now.
4. The show has just begun. You are a bit late.
5. She has been happy since she had a computer.
6. She has done her homework recently.
7. They have not handed in their essay yet.
8. In 2030, everyone will study at home using a computer.
9. My brother will be 15 years old next Sunday.
10. I have been waiting for her since half past six.

7.D
1. Have you met the new student yet?
2. I lost my handbag yesterday.
3. We are having some friends to lunch tomorrow.
4. She has already finished her homework.
5. My sister is getting married next month.
6. My father often drinks tea after breakfast.
7. John is going swimming tomorrow afternoon.
8. What did you eat yesterday morning?
9. Your father is repairing your motorbike at the moment.
10. Tomorrow, she will invite all friends to her birthday.