[spongebobism]

idlewords mentioned some good ones. While English doesn't have many moods, it still has relatively many verb forms (just take a look at past tenses: I ate, I've eaten, I had eaten, I was eating, I have been eating, I had been eating...). In most contexts, only one of them is idiomatic, and knowing which one takes a lot of studying. Also, English has a fixed order for adjectives [1]. AFAIK, this is unusual cross-linguistically - at least in my native language, "big red ball" and "red big ball" would both be idiomatic. If you're really curious, you can take a look at the contents of an English grammar for advanced learners. What gets a lot of chapters, probably trips up a lot of learners. [2]

[1] https://www.espressoenglish.net/order-of-adjectives-in-engli... [2] https://assets.cambridge.org/97811076/99892/frontmatter/9781...