Function of 지 in this sentence? Hi someone wrote this to me but I don't quite understand. 아프지 마요. 감사합니다.

-고 있다 / -고 없다 ? 공부하고 있어요. = I am studying. So... 공부하고 없어요. = I am not studying? Does it work like that?

For native English speakers: to do vs doing I was thinking as I learn my target language about infinitive vs -ing verb forms in the following examples. How do we decide which to use? Is it arbitrary? Do we follow a rule I've never put a name to? Your opinions, please! I like to cook. vs. I like cooking. She likes to swim. vs. She likes swimming. Etc :-)

Explain individual words to me, please? 상쾌한 아침이에요. 좋은 하루 되세요. I understand it means: It is a new morning. Have a good day. But the only word I really recognize is 아침. Does anyone have time to explain more fully? 고마워요!

How this works 다음주부터 열심히 공부합시다! Someone wrote this to me and gave me the following meaning: Let's study hard next week. But I don't understand how the structure works within the words. Can anyone explain in more detail? I took a solid week away from language learning and it feels like I forgot so much!!

How do I say...? Would someone please translate that exact question for me?

Korean online dictionary Would someone recommend a good English>Korean online dictionary for me?  Thanks!

Technical italki question... What does the check mark in a speech bubble mean?  I often see it as part of a user profile.

진짜예요 means? What does this mean? I don't understand how 진짜 can be a noun. 진짜 = real?