OK I get it, I know how to say hello and goodbye!!
I'm on level 4 of Greetings and so far all that has been taught me is the same lesson over and over--hello, goodbye, and good. Not even "bad!" Not even "how are you?" (a simple transition from 'ni hao' to 'ni hao ma'). Not even 'nin hao', a more formal term of address. This is getting ridiculous, and really repetitive.
I just found this on google: https://www.fluentu.com/blog/chinese/2014/01/23/say-hello-chinese-greetings/
and Duolingo hasn't covered a single one of these! Surely the "greetings" portion of the course can't just be an eternal purgatory of "ni hao" and "zai jian" and we'll get there eventually... right? Right?
It's true that you can spend a lot of time without seemingly much progress. I guess the idea is to get us used to those Chinese characters with almost endless repetition. However, you can speed up by clicking the "key" button, taking a test and jumping one level at a time without much pain. There is more to come, and every individual has his/her own pace. Click the key button and see how it works for you.
I have studied many other lessons, I was just hoping that there would be some other greetings too
Well, yeah. I got to that too lol. But it seems silly to have 4 levels identical to level 1.
You obviously seem to have gotten the hang of hello, goodbye, and good, so why don't you study some of the other lessons? Or you could skip to level 5 of Greetings so you don't have to do it anymore.