Use Present Perfect or Present Indefinite; 1. Our family (to eat) dinner at home on Saturdays and Sundays....

1. Our family eats dinner at home on Saturdays and Sundays. (Present Indefinite)
2. Our family has been eating dinner at home since grandma came to live with us. (Present Perfect)
3. I know Alice very well. (Present Indefinite)
4. I have known Alice since school time. (Present Perfect)
5. Mr. Brook is our English teacher. (Present Indefinite)
6. Mr. Brook has been our English teacher for a year. (Present Perfect)
7. They have been married for 10 years. (Present Perfect)
8. They are married. (Present Indefinite)
9. Have you lived in Moscow all your life? (Present Perfect)
10. Do you live in Moscow? (Present Indefinite)
11. Has he worked at this office long? (Present Perfect)
12. Does he work at this office? (Present Indefinite)

To determine whether to use the Present Perfect or the Present Indefinite (Simple Present) tense, it's important to understand the contexts in which each tense is used.

Present Indefinite (Simple Present):

• This tense is used for actions that are habitual or generally true.
• It describes routines, habits, or facts.

Present Perfect:

• This tense is used for actions that occurred at an unspecified time and have relevance to the present.
• It describes actions or situations that started in the past and continue into the present, or have consequences in the present.

Now, let's apply these rules to each sentence:

1. Our family (to eat) dinner at home on Saturdays and Sundays.

   • The action is a habitual routine.
   • Answer: "Our family eats dinner at home on Saturdays and Sundays."

2. Our family (to eat) dinner at home since grandma came to live with us.

   • The action started in the past and continues to the present.
   • Answer: "Our family has eaten dinner at home since grandma came to live with us."

3. I (to know) Alice very well.

   • This is a general statement about current knowledge.
   • Answer: "I know Alice very well."

4. I (to know) Alice since school time.

   • The knowing started in the past and continues to the present.
   • Answer: "I have known Alice since school time."

5. Mr. Brook (to be) our English teacher.

   • This is a present fact or occupation.
   • Answer: "Mr. Brook is our English teacher."

6. Mr. Brook (to be) our English teacher for a year.

   • The teaching started in the past and continues to the present.
   • Answer: "Mr. Brook has been our English teacher for a year."

7. They (to be married) for 10 years.

   • The marriage started in the past and continues to the present.
   • Answer: "They have been married for 10 years."

8. They (to be married).

   • This is a present state or fact.
   • Answer: "They are married."

9. You (to live) in Moscow all your life?

   • The question implies a duration from past to present.
   • Answer: "Have you lived in Moscow all your life?"

10. You (to live) in Moscow?

    • This is a question about current residence.
    • Answer: "Do you live in Moscow?"

11. He (to work) at this office long?

    • The question implies a duration from past to present.
    • Answer: "Has he worked at this office long?"

12. He (to work) at this office?

    • This is a question about current employment.
    • Answer: "Does he work at this office?"

By understanding the context and whether the action is ongoing or habitual, you can correctly choose between the Present Perfect and Present Indefinite tenses.

1. Present Indefinite: Our family eats dinner at home on Saturdays and Sundays.
2. Present Perfect: Our family has been eating dinner at home since grandma came to live with us.
3. Present Perfect: I have known Alice very well.
4. Present Perfect: I have known Alice since school time.
5. Present Indefinite: Mr. Brook is our English teacher.
6. Present Perfect: Mr. Brook has been our English teacher for a year.
7. Present Perfect: They have been married for 10 years.
8. Present Indefinite: They are married.
9. Present Perfect: Have you lived in Moscow all your life?
10. Present Indefinite: Do you live in Moscow?
11. Present Perfect: Has he worked at this office long?
12. Present Indefinite: Does he work at this office?