Here are the suggested answers for the sentences based on the given options A, B, C, or D:

**Ex7: Choose A, B, C, or D to complete each of the following sentences:**

1. The new film is about a boy **C. who** can speak several languages.
2. Lan is a student **C. whose** English vocabulary is the strongest in our class.
3. The English-English dictionary **B. which** I bought at this store a few days ago is expensive.
4. That’s the writer **B. which** historical fiction I recommended.
5. **A. who**. Brazil is one of the largest English-speaking countries in the world.
6. **A. who**. Nigeria is a country that is one of the largest English-speaking countries in the world.
7. That’s the man **B. which** I spoke to at the English Teaching Conference the other day.
8. That’s the student **D. whose** name I forgot.
9. **A. who**.

**Ex8: Choose A, B, C, or D to indicate the underlined part that needs correction:**

1. A. She B. C. D. **questions** ➜ C. is the correct answer.
2. A. a B. **C. exercises** ➜ C. is the correct answer.
3. A. Do B. you C. know D. **which** ➜ A. is the correct answer.
4. A. know B. D. **translate** ➜ D. is the correct answer.
5. A. The exchange study which knowledge of English grammar is excellent is very friendly. ➜ C. is the correct answer.
6. D. **friendly** ➜ is correct as is.
7. B. **C. Is** ➜ B. is the correct answer.
8. A. where I can learn English. ➜ D. is the correct answer.

You may need to double-check specific context or grammar rules for complete accuracy.