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Hello,

Could you correct these phrases, please?

We were shown many beautiful pictures at a musem.

We were shown many beautiful pictures at the museum.

We were shown many beautiful pictures in a museum.

We were shown many beautiful pictures in the museum.

Thanks
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Nina_NiaCould you correct these phrases, please? We were shown many beautiful pictures at a musem. We were shown many beautiful pictures at the museum. We were shown many beautiful pictures in a museum. We were shown many beautiful pictures in the museum.
Grammatically, they are all OK.

The definite articles "the" and "a" mark a noun phrase as definite and indefinite respectively (hence their names).

So, use the definite noun phrase "the museum" only if you assume the addressee will be able to identify the museum you're referring to. Otherwise, use the indefinite noun phrase "a museum"

"In" and "at" are freely interchangeable here. Either is fine.

BillJ
Comments  
They are all correct but may be used in different circumstances. When 'the museum' is used, I would expect the museum to have been mentioned previously.
Paul
 BillJ's reply was promoted to an answer.