Tough sounds (advanced)
As an elementary learner of Mandarin Chinese, you should have already gotten a handle on most of the "tough sounds" of the language. Unfortunately, being able to pronounce a word when you drop everything and focus super hard on that one- or two-syllable word isn't quite good enough. Time to push on into more challenging phrases before you can truthfully say you have mastered the really challenging sounds of the language.
B1 Tough Sounds
Although this list is shorter than the elementary-level (A2) Tough Sounds list, there are still some sounds that intermediate learners need to work on. By combining and stringing together sounds that were hard for you as an elementary learner, you can increase the challenge and get your pronunciation to a really excellent level.
You don't have to do those in order, but you definitely want to master them all.
Note that each of these "tough sounds" has a corresponding easier A2 tough sound. If these are too challenging for you, you can start with those A2 tough sounds.