The correct option to fill the gaps in the sentences is B. so is, so did. Let's break down why this is the best choice and analyze the other options. Step-by-Step Explanation

1. Understanding the Context:
2. The first part of the sentence is "I am a student and .... Musa." This indicates that we are talking about two subjects: "I" and "Musa." The verb must agree with the subject in terms of tense and form.
3. The second part is "I left for the university, and .... Musa." Here, we are discussing an action that has already happened (leaving for the university).
4. Analyzing the Options:
5. Option A: was, does
   • "I am a student and was Musa." This is incorrect because "was" is past tense, while "am" is present tense. The two tenses do not match.
   • "I left for the university, and does Musa." This is also incorrect because "does" is present tense, which does not fit with the past action of "left."
6. Option B: so is, so did
   • "I am a student and so is Musa." This is correct because "so is" indicates that Musa is also a student in the present tense, matching the present tense of "I am."
   • "I left for the university, and so did Musa." This is also correct because "so did" indicates that Musa also left for the university, matching the past tense of "I left."
7. Option C: so was, so does
   • "I am a student and so was Musa." This is incorrect because "so was" implies that Musa was a student in the past, which does not match the present tense of "I am."
   • "I left for the university, and so does Musa." This is incorrect because "does" is present tense, which does not fit with the past action of "left."
8. Option D: he is, he did
   • "I am a student and he is Musa." This is incorrect because it changes the subject from Musa to "he," which is not consistent with the original sentence structure.
   • "I left for the university, and he did Musa." This is incorrect because "he did" does not make sense in this context; it lacks a verb that indicates what Musa did.

Summary of the Correct Answer

• Correct Option: B. so is, so did
• "I am a student and so is Musa." (Both are students in the present)
• "I left for the university, and so did Musa." (Both left for the university in the past)

Revision Summary

• Option B is correct because it maintains the correct tense agreement and subject consistency.
• Option A is incorrect due to mismatched tenses.
• Option C is incorrect because it incorrectly uses past tense for a present statement.
• Option D is incorrect as it changes the subject and lacks clarity in the second part.

By understanding the importance of tense agreement and subject consistency, you can effectively choose the correct options in similar sentence completion tasks.