I was writing this one sentence and confused with prepositions. Additionally, I would like to know if there are other grammatical errors besides these two prepositions.
….They are always helpful for reminding me of what to focus on in order to improve my English.
Thank you for your help.
Best Answer
Looking at the Oxford Dictionary definitions for the two prepositions that you proposed:
Both prepositions are correct: in would focus on their involvement in your studies, and for would focus on their purpose.
If you look at the entry for remind in the Cambridge dictionary, you will see that one of the possible usages is (+ that), for example
that is a relative pronoun here, and you can substitute other relative pronouns: what, who why, which, etc. so it's OK to say
It is not necessary to add of before what in this sentence. It's not wrong to include of, but it sounds a little strange.