1. Subject-verb agreement: The subject and the verb in a sentence should agree in number, i.e., a singular subject should have a singular verb, and a plural subject should have a plural verb.

2. Prepositions: A preposition is a word that shows the relationship between a noun or pronoun and other words in a sentence. Some common prepositions include in, on, at, to, from, with, etc.

4. Adjectives: Adjectives are words that describe or modify nouns or pronouns. They can be used to indicate size, shape, color, etc.

5. Verbs: Verbs are words that indicate an action, occurrence, or state of being. They can be in different tenses - past, present, and future.