When someone asks you "What would you do if you were in my place?" in Spanish, the answer is harías, the conditional form. The other forms—haz, hiciera and hagas—serve different purposes entirely, and mixing them up makes you sound unnatural.
Spanish gives you four main ways to transform the verb "hacer" (to do), and each one signals a different kind of action or instruction. Understanding which one to pick is the difference between sounding fluent and sounding like you are guessing.
Haz: Direct Commands Only
Use haz when you are telling someone to do something right now. It is the imperative form, the voice you use when you want immediate action. If your friend is sitting on the couch and you want them to help you move a box, you say "Haz algo, por favor" (Do something, please). The moment you are not giving a direct order, haz is wrong. You cannot use it in a question, a hypothetical situation, or a polite suggestion.
Harías: Hypothetical and Conditional Situations
Harías is the conditional tense, and it answers the question "What would you do?" Use it when you are imagining a situation that has not happened yet, or when you are asking someone what their choice would be in a different circumstance. "Uf, estoy muy estresado, que harías tú en mi lugar?" (Oof, I am very stressed, what would you do in my place?) This is the sentence structure people actually use when they want advice based on imagination. Harías works because it says "if the situation were different, what would your action be?"
Hiciera and Hagas: Subjunctive Moods
Both hiciera and hagas are subjunctive forms, which means they belong in completely different sentence structures. The subjunctive expresses doubt, desire, emotion, or unreality. You would never use either one in the "what would you do" question above. Hiciera appears in sentences like "Espero que hiciera lo correcto" (I hope he did the right thing), where you are expressing a wish or uncertainty about the past. Hagas fits into requests like "Quiero que hagas la tarea" (I want you to do the homework), where someone is asking or demanding that another person perform an action. The subjunctive is not about what someone would do in a hypothetical situation; it is about expressing your attitude toward an action.
The Big Picture: Context is Everything
Spanish verb tenses are not abstract grammar rules floating in space. They exist because native speakers need to express real differences in meaning. Haz is command. Harías is imagination. Hiciera and hagas are about desire, doubt, or unreality. Once you see each form in its natural habitat, choosing the right one becomes instinctive.
The best way to make this instinct stick is to hear and use these forms in real conversation. PBC Languages runs small group classes with maximum four students, which means you actually get time to speak and ask questions. You can also join a free language exchange with a native Spanish speaker through PBC Languages, where someone who lives in Spain or Latin America will help you practice these exact situations. You might say "Que harías si tuvieras un millón de euros?" (What would you do if you had a million euros?) and hear how a native speaker answers, which teaches you the pattern far faster than any worksheet.
Consistency matters more than intensity. A conversation once a week with a real person beats an hour of solo practice. Show up, use the language, ask when you are confused, and your ear will tune itself to the right forms.
