Question

i) correct the text by inserting one comma.

ii) huh since ive been reading so much lately, my vocabulary has improved tremendously.

Explanation:

The interjection "Huh" is a standalone introductory expression that needs to be set off from the rest of the sentence with a comma for proper punctuation.

Answer:

Huh, since I've been reading so much lately, my vocabulary has improved tremendously.