Si yo fuera tú, aceptaría la oferta.

それぞれの単語がその位置にある理由

1. 1
   Si + imperfect subjunctive: fuera (from ser) sets up an imaginary situation. Si yo fuera tú is the classic way to give advice. Hypothetical conditions: si + imperfect subjunctive →
2. 2
   yo is kept: fuera is the same form for yo and él / ella, and the pronoun contrasts with tú. Imperfect subjunctive: forms and uses →
3. 3
   After ser comes the subject form: yo fuera tú, never ✗ fuera ti. Subject pronouns and forms of address: tú, usted, ustedes →
4. 4
   The advice goes in the conditional: aceptaría = I would accept. Conditional: forms and uses →

• Si yo fuese tú, aceptaría la oferta.
• Yo en tu lugar, aceptaría la oferta.