Giúp mình với

Here are the answers: 1. The correct word is "which" is incorrect in this context, the correct word should be "that" or "when" but "that" is more suitable for object relative pronoun whereas "when" isn't. However, in informal context, it could be that the speaker could use "which" in this context for an inanimate object like a dictionary. The correct answer here is "which" in informal contexts. 2. The correct word is "why". The reason why is a subordinate clause indicating that the clause is a dependent clause. "Which" does not suit this situation. 3. The correct word is "when". This indicates a specific time, July was a period of time when that incident occurred. 4. The correct word is "whose". This is a possessive form that is often used in formal or literary contexts, to describe something belonging to someone, in this case, the British accent. 5. The correct word is "who". The subject is a person in this case and is used as the subject of the sentence. Here are the completed sentences: 1. The man whose job involves working with foreigners can speak English proficiently. 2. I still remember the first day when Phuong gave a presentation about her experiences learning foreign languages. 3. English is a language that is widely used in international communication. 4. Do you know the country where English was first spoken? 5. I'm not sure of the reason why Jack chooses Korean as a subject to study at the university. Here are the combined sentences using relative pronouns: 1. Quan, who usually helps me with my English grammar exercises, is one of my classmates. 2. You shouldn't look up the meaning of all of the words that you may find in the reading text. 3. The school library, where we sometimes discuss our difficulties in studying, is the place. 4. Can you explain the reason for which you can't spend more time learning vocabulary? Alternative: Can you explain why you can't spend more time learning vocabulary? Or: The reason you can't spend more time learning vocabulary, is this? Alternative: Can you explain the reason why you can't spend more time learning vocabulary? 5. In order to borrow these reference books, you must ask Mrs. Smith, who is the librarian. 1. • True 2. • False 3. • False 4. • True 5. • True