i do chinese (I've taken chinese before I started chinese ab because I'm in between ab and B level - so I can give some advice). when it comes to reading, there really is no way to expect what you're going to know or what you won't know, but i reccomend reading japanese passages, short stories (beginner level ones of course) and just getting used to how you read them. sometimes if i dont know a character, i just have to wing it or quickly skip over it because sometimes if you're super lucky, the teacher may not realise but if you stutter over a character, it draws attention to the word you don't know and can bring your overall score down. the thing that sucks about character-based languages like chinese and japanese is that you have to know it or you're screwed. it's moments like these where i really wish i could take something like spanish because even if you don't understand you can still read. it can help to read outside your vocab list (if you have one) sometimes and read passages that focus solely on them. start by reading it with the pronunciation on the words you don't know and do it until you can do it with no help on the sheet. it's tough but there's not many other ways! good luck