1. – What are you doing? – I'm repairing my son's bicycle. I (do) it for two hours. 2. I'll call for...

To answer these questions, we need to focus on the appropriate use of verb tenses in English, particularly the Present Perfect Continuous and Present Perfect tenses. These tenses are used to express actions that started in the past and continue into the present, or have effects on the present.

1. I'm repairing my son's bicycle. I have been doing it for two hours.

   • Explanation: The Present Perfect Continuous tense ("have been doing") is used here to indicate that the action of repairing started two hours ago and is still ongoing.

2. I'll call for an ambulance. She has been getting weaker and weaker since she had breakfast.

   • Explanation: The Present Perfect Continuous tense ("has been getting") is used to express a continuous process of deterioration in her condition that started after breakfast and continues up to the present moment.

3. Hurry up, John. I'm waiting for you. You have been having a bath for an hour.

   • Explanation: The Present Perfect Continuous tense ("have been having") emphasizes the duration of John's action (bathing) that started an hour ago and is still happening.

4. Who is that man standing on the corner? He has been standing there for the last half an hour.

   • Explanation: The Present Perfect Continuous tense ("has been standing") indicates the man started standing there half an hour ago and remains there now.

5. Where is Dad? I have been waiting for him since 6 p.m. We are going to be late to the concert.

   • Explanation: The Present Perfect Continuous tense ("have been waiting") shows that the action of waiting began at 6 p.m. and is still ongoing.

6. I can't stand it any more. Those people have been quarrelling since breakfast.

   • Explanation: The Present Perfect Continuous tense ("have been quarrelling") is used to show that the quarrelling started at breakfast and has continued up to now.

7. Jim works as a sales manager. Really? He has been selling washing machines for three months.

   • Explanation: The Present Perfect Continuous tense ("has been selling") indicates the ongoing action of selling washing machines over the past three months.

8. Dora is playing the piano. She has been playing the piano since I came.

   • Explanation: The Present Perfect Continuous tense ("has been playing") highlights that the action started when the speaker arrived and is still happening.

9. Aren't you going to tell me what you have been doing in my absence?

   • Explanation: The Present Perfect Continuous tense ("have been doing") is used to inquire about activities that occurred during the speaker's absence and may still be relevant now.

10. How long have you been sitting here?

    • Explanation: The Present Perfect Continuous tense ("have been sitting") is appropriate for asking about the duration of the action that started in the past and continues into the present.

11. Michael, I have been trying to get you all day!

    • Explanation: The Present Perfect Continuous tense ("have been trying") indicates a repeated effort that started earlier in the day and continues up to now.

12. I'll go and wash my eyes. I don't want my husband to see I have been crying.

    • Explanation: The Present Perfect Continuous tense ("have been crying") is used to describe an action that has recently taken place and may have visible effects in the present.

13. The amount of crime has been increasing for the last ten years and we can't stop this process.

    • Explanation: The Present Perfect Continuous tense ("has been increasing") is suitable here to describe a trend or process that started in the past and continues into the present.

In all these sentences, the Present Perfect Continuous tense helps convey the continuity and duration of actions that are relevant to the present moment.

1. I have been repairing my son's bicycle for two hours.
2. She has been getting weaker and weaker since she had breakfast.
3. You have been having a bath for an hour.
4. He has been standing there for the last half an hour.
5. I have been waiting for Dad since 6 p.m.
6. Those people have been quarreling since breakfast.
7. He has been selling washing machines for three months.
8. Dora has been playing the piano since I came.
9. Aren't you going to tell me what you have been doing in my absence?
10. How long have you been sitting here?
11. I have been trying to get you all day, Michael!
12. I'll go and wash my eyes. I don't want my husband to see that I have been crying.
13. The amount of crime has been increasing for the last ten years and we can't stop this process.