Fix the grammar mistakes: Using the previous examples, the P-80 jet was used for close to 30 years before being replaced completely, while the HIV vaccine may be in use forever if the vaccine undergoes successful researches.
The P-80 jet was used for close to 30 years before being replaced completely.
Correct: The P-80 jet was used for close to 30 years before being replaced completely.
Correct: The P-80 jet was used for close to 30 years before being replaced completely.
Correct: The P-80 jet was used for close to 30 years before being replaced completely.
Correct: The P-80 jet was used
The P-80 jet was used for close to 30 years before being replaced completely, while the HIV vaccine may be in use forever if the vaccine undergoes successful researches.
The P-80 jet was used for close to 30 years before being replaced completely, while the HIV vaccine may be in use forever if the vaccine undergoes successful researches.
The P-80 jet was used for close to 30 years before being replaced completely, while the HIV vaccine may be