Question 1:

Choose the sentence that is grammatically correct:

Explanation: The sentence "She has been studying for the exam all week." is grammatically correct. The pronoun "she" is used correctly, and the verb tense is appropriate.

Question 2:

Choose the sentence that is grammatically correct:

Explanation: The sentence "The cat is sleeping on the mat." is grammatically correct. The subject-verb agreement is appropriate, and the pronoun "the cat" is used correctly.

Question 3:

Choose the sentence that is grammatically correct:

Explanation: The sentence "He plays the guitar very well." is grammatically correct. The subject-verb agreement is appropriate, and the adverb "very well" is used correctly to describe the verb "plays."

Question 4:

Choose the sentence that is grammatically correct:

Explanation: The sentence "They have already left for the airport." is grammatically correct. The subject-verb agreement is appropriate, and the adverb "already" is used correctly to describe the verb "have left."

Question 5:

Choose the sentence that is grammatically correct:

Explanation: The sentence "She is an intelligent and hardworking student." is grammatically correct. The adjectives "intelligent" and "hardworking" are used correctly to describe the noun "student," and the subject-verb agreement is appropriate.