1. I haven't read Harry Potter yet.
2. I don't read Harry Potter yet.
3. I didn't read Harry Potter yet.
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Which expressions are not grammatical?
Is #2 or #3 grammatical?
#1 is correct.
#s 2 and 3 are not.
PS -- #3 could be correct if "yet" were removed.
#1 is right
Out of the three statements, only #1 is grammatically correct. Both #2 and #3 are not grammatical. The correct forms would be:
1. I haven't read Harry Potter yet. (This sentence implies that you still have the possibility of reading Harry Potter in the future.)
2. *I don't read Harry Potter yet. (This sentence is not grammatical because the present simple tense "don't read" is used incorrectly with the word "yet." Instead, you could say "I haven't started reading Harry Potter yet.")
3. *I didn't read Harry Potter yet. (This sentence is not grammatical because the past simple tense "didn't read" is used incorrectly with the word "yet." Instead, you could say "I haven't read Harry Potter yet" or "I still haven't read Harry Potter.")
To determine whether a sentence or expression is grammatically correct, it's important to consider the appropriate verb tense and word choice. In this case, using the present perfect tense ("haven't read") correctly conveys the idea that the action of reading Harry Potter has not been completed up until now.