You need to use 'I haven't eaten it for a month.' For never, use this when you haven't done this thing in your life. For example, 'I have never done a bungee jump.' ' I have never flown in a plane' etc.

when you say: I haven't eaten in a month, you mean that you used to eat before, but you stopped eating a month ago. You can say: I have never eaten mango before, and this means that this is the first time you eat a mango in your life.

Hi! Yes, the sentence is correct! You got it right with your explanation as well! And yes you can use "never" to mention the specific time you haven't done something. This is also common to spoken English. example of "NEVER" as follows! 1.) I have never eaten pasta in a year. (Maybe you were in diet for 1 year, and you decided to skip eating pasta for that specific time, and maybe you are already eating it now that 1 year has passed) 2.) I have never been to Netherlands. (You have never travelled there your whole life) 3.) He's never been in love. (Not a single time that he had this experience in his entire life ;) 4.) She never forgave me. (After a quarrel your friend have not forgiven you about that specific incident.) 5. I never wanted to hurt you. (You had no intention to hurt someone ever, but it happened.) Have a great day!

Hi Maki! This is a good question especially if you are learning present perfect tense for the first time. Present perfect tense talks about your life experiences and to do this, we use "ever" and "never". Never means "at no time" In your example, you can have these following sentences; 1. I used to eat this before. 2. I have never eaten it since last month. 3. I have never eaten it for a month. 4. I haven't ever eaten it fo a month or since last month. hope this really helps you.