Regency and crase

The Core Idea

Regency is the preposition pattern a verb, noun, or adjective requires. Crase marks the fusion of a with another a, usually before a feminine noun phrase.
Regency errors and missing crases are classic high-visibility issues in formal Portuguese. A good mental map here pays off in writing, reading, and exams.

Structure Snapshot

• verb or noun + required preposition / a + a(s) = à(s)

Main Rules at a Glance

How It Works

1. Many verbs require a specific preposition: "gostar de", "precisar de", "obedecer a", "assistir a".
2. Nouns and adjectives can also require prepositions: "medo de", "favorável a".
3. Crase usually appears when a word requires "a" and the next feminine phrase also begins with "a": "vou à escola".
4. No crase appears before masculine nouns, verbs, or most repeated words without the needed fusion.

Usage and Register

• The biggest practical step is to learn regency together with the verb or noun from the start.