Hello. I will be very grateful for your help.

1)Which article is correct in the context: "The ambassador gave a/the(?)promise that his country would not interfere"?
2)Do you think it's possible to use "carry out" or "realise" with "visit", for example, "The premier carried out / realized an official visit to Zimbabwe"?
3)Which word is correct, cause or reason, (maybe, both?)in the context "Civilian deaths are the main cause of / reason for(?)tension between Nato and Afghan officials".
4)Do you think it's possible to say "after a year" in the sentence "They will leave the country after a year" or is it only "in a year"?
5)Is it possible to use the infinitive after "arrange", for example "they arranged to meet in Paris early next year"?
Thank you very much for your help.

1)Which article is correct in the context: "The ambassador gave a/the(?)promise that his country would not interfere"?

The article "a" is better, but even better than that is to rephrase the sentence: The ambassador promised that his country would not interfere.

2)Do you think it's possible to use "carry out" or "realise" with "visit", for example, "The premier carried out / realized an official visit to Zimbabwe"?
Better phrasing: The premier made an official visit...

3)Which word is correct, cause or reason, (maybe, both?)in the context "Civilian deaths are the main cause of / reason for(?)tension between Nato and Afghan officials".
Both work fine. I prefer "reason," but both are correct.

4)Do you think it's possible to say "after a year" in the sentence "They will leave the country after a year" or is it only "in a year"?
Both are correct.

5)Is it possible to use the infinitive after "arrange", for example "they arranged to meet in Paris early next year"?
Yes, that's correct.

1. a

2. "carried out" is much better
3. cause of
4. "in a year" means in the next 12 months, and is clearer. Otherwise it is not clear when the time counting starts.
5. yes, the infinitive use is perfect

1) In the context you provided, both "a" and "the" are grammatically correct. However, they slightly differ in meaning.

- "The ambassador gave the promise" implies that there was a specific promise made by the ambassador, and it is known or referenced earlier in the conversation.
- "The ambassador gave a promise" implies that the ambassador made a promise, but it may not be a specific or previously mentioned promise.

2) Both "carry out" and "realize" can be used with "visit" in different contexts.
- "The premier carried out an official visit to Zimbabwe" suggests that the visit was successfully completed or executed.
- "The premier realized an official visit to Zimbabwe" implies that the visit was actualized or made into a reality.

3) In the context you provided, both "cause" and "reason" can be used, but they have slightly different implications.
- "Civilian deaths are the main cause of tension" suggests that the occurrence of civilian deaths directly leads to tension between NATO and Afghan officials.
- "Civilian deaths are the main reason for tension" implies that civilian deaths serve as the primary explanation or justification for the tension between NATO and Afghan officials.

4) Both "after a year" and "in a year" are grammatically correct and can be used, but they have different meanings.
- "They will leave the country after a year" means they will depart one year from the reference point or starting time.
- "They will leave the country in a year" means they will depart one year from the current time.

5) Yes, it is possible to use the infinitive after "arrange" as you mentioned in the example sentence: "They arranged to meet in Paris early next year." The verb "arrange" can be followed by the infinitive form of a verb to express planned actions or events. In this case, the action of meeting in Paris was planned and scheduled for early next year.

I hope this helps! Let me know if you have any more questions.