I left out the following two sentences. Thank you very much.
1) My sister is in her second year a university.
2) My sister just entered her second year of university degree in medicine in Turin.
1. ... at university.
or
... in University of Genoa. (or whatever the name of the university is)
2. ... her second year of university in Turin, working on her degree in medicine.
No problem! Here are the corrected sentences:
1) My sister is in her second year at university.
To check the correctness of this sentence, we need to verify the usage of the article "a" before "university." Since it is not necessary to use an article before the word "university," the correct sentence would be: "My sister is in her second year at university."
2) My sister just entered her second year of a university degree in medicine in Turin.
To check the correctness of this sentence, we need to examine the usage of articles and prepositions. Since it is appropriate to use the article "a" before "university degree" to indicate a nonspecific degree, the sentence is grammatically correct. However, to improve clarity, we could remove the article "a" before "university degree" and revise the sentence as follows: "My sister just entered her second year of a university degree in medicine in Turin."