Oh, I suppose different lists could be made by different syllabus creators, but such things as: Word order (SVO, SVC, etc) Countability of nouns Articles Verb tenses Verb phrase construction Subject-Verb agreement etc. These things have to be emphasized in teaching the language, especially the structures that have no parallels in the L1.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.