An old house 19. A man was tired of living in his old house. He decided to sell it and buy a
one. (GOOD)
20. He attempted to sell it but was not successful so at last he decided to solve the problem by
an
estate agent. (USE)
21. The estate agent advertised the house and the owner saw a wonderful description of the house and gardens, Then he said, "I can see that I like my house very much and don't want to sell it". (IT)
Isaac Newton's dinner
22. Newton was very absent-minded. One day a gentleman came to see him but he
that Isaac Newton
was busy and he could see him later. (TELL)
23. As it was dinner time, the visitor
in the dining-room to wait for the scientist. (SIT)
24. An hour passed but Newton
so the gentleman ate the scientist's dinner. (NOT APPEAR)
25. When Newton came and saw no dinner, he exclaimed, "What a strange set we scientists are! I quite forgot that I
already". (DINE)
Check
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19. A man was tired of living in his old house. He decided to sell it and buy a new one. (GOOD)

To solve this question in a grammatically correct way, we need to replace the word "one" with a noun that refers to a new house. Let's use the word "another" instead. The sentence would then be: "A man was tired of living in his old house. He decided to sell it and buy another."

20. He attempted to sell it but was not successful, so at last he decided to solve the problem by using an estate agent. (USE)

In this sentence, the word "agent" is already given. We need to add an article before it. Let's use the definite article "an" before the word "estate." The sentence would then be: "He attempted to sell it but was not successful, so at last he decided to solve the problem by using an estate agent."

21. The estate agent advertised the house, and the owner saw a wonderful description of the house and gardens. Then he said, "I can see that I like my house very much and don't want to sell it". (IT)

In this sentence, the pronoun "it" refers to "the house" mentioned earlier. We can replace the pronoun with the noun "the house" to make the sentence clearer. The sentence would then be: "The estate agent advertised the house, and the owner saw a wonderful description of the house and gardens. Then he said, 'I can see that I like my house very much and don't want to sell the house'."

Isaac Newton's dinner

22. Newton was very absent-minded. One day, a gentleman came to see him but he was told that Isaac Newton was busy and he could see him later. (TELL)

To correct this sentence, we need to add the preposition "by" before the word "Isaac." Additionally, we need to change the verb form to match the past tense of "told." The sentence would then be: "Newton was very absent-minded. One day, a gentleman came to see him but he was told by Isaac Newton that he was busy and that he could see him later."

23. As it was dinner time, the visitor sat in the dining-room to wait for the scientist. (SIT)

This sentence is already correct and does not require any changes.

24. An hour passed, but Newton did not appear, so the gentleman ate the scientist's dinner. (NOT APPEAR)

To make this sentence grammatically correct, we need to use the negative form of the verb "appear." Instead of "did not appear," let's use "didn't appear." The sentence would then be: "An hour passed, but Newton didn't appear, so the gentleman ate the scientist's dinner."

25. When Newton came and saw no dinner, he exclaimed, "What a strange set we scientists are! I quite forgot that I had already dined." (DINE)

To make this sentence grammatically correct, we need to add the auxiliary verb "had" before the main verb "already." The sentence would then be: "When Newton came and saw no dinner, he exclaimed, 'What a strange set we scientists are! I quite forgot that I had already dined.'"

Check:

After making the necessary corrections, the passage should look as follows:
"19. A man was tired of living in his old house. He decided to sell it and buy another.
20. He attempted to sell it but was not successful, so at last he decided to solve the problem by using an estate agent.
21. The estate agent advertised the house, and the owner saw a wonderful description of the house and gardens. Then he said, 'I can see that I like my house very much and don't want to sell the house.'
22. Newton was very absent-minded. One day, a gentleman came to see him but he was told by Isaac Newton that he was busy and that he could see him later.
23. As it was dinner time, the visitor sat in the dining-room to wait for the scientist.
24. An hour passed, but Newton didn't appear, so the gentleman ate the scientist's dinner.
25. When Newton came and saw no dinner, he exclaimed, 'What a strange set we scientists are! I quite forgot that I had already dined.'"