Real conditional clauses with ako

Half of all advice is an if-sentence: if your head hurts, take a pill; if you have a fever, stay in bed. Serbian builds these with ako ("if") and, as in English, the sentence has two halves: the condition (the ako-clause) and the result (the main clause). The condition can come first or second. When it comes first, a comma separates the two halves; when it comes second, there is no comma.

The condition: ako plus the present

The normal way to state a real condition — something that may well happen — is ako followed by the verb in the ordinary present tense. This covers conditions about now and about the future, exactly as English does: Ako imaš temperaturu is both "if you have a fever (now)" and "if you have a fever (tomorrow)".

The result clause then says what to do or what will follow. Three kinds of result are common: an imperative (advice or an order), the future (a prediction) and, less often, the plain present (a general truth or a rule).

Negation works as everywhere else: ako ne plus the verb (ako ne uzmeš), or the fused negatives you already know (ako nemaš, ako nisi). The unstressed clitics — se, te, mi, je and the rest — sit straight after ako, because ako is the first word of its clause: Ako te boli glava..., Ako se osećaš loše....

The condition: ako plus the future

Here Serbian does something English cannot. English forbids will after if — you say "if you go", never "if you will go". Serbian allows the future after ako, and uses it when the condition is about someone's plan or intention: Ako ćeš sutra ići kod lekara, ići ću s tobom — "if you're going to the doctor tomorrow, I'll come with you". The English that matches it is usually "if you're going to..." or "if you will..." in the sense of "if you intend to".

Both are correct: Ako sutra ideš kod lekara (present) and Ako ćeš sutra ići kod lekara (future). The present is the neutral choice; the future adds the sense of a plan or a decision already made. What you must not do is carry the English rule across and treat ako ću / ako ćeš as an error — it is ordinary Serbian.

kad, not ako, for what always or certainly happens

Ako means the condition is genuinely open: maybe you have a fever, maybe you do not. When the thing is not in doubt — it happens every time, or it is certain to come — Serbian switches to kad ("when", "whenever"). Kad imam temperaturu, ležim u krevetu is "whenever I have a fever, I lie in bed": a habit, not a possibility. The verb after kad is the present, and the result is most often the present too (a habit) or an imperative (standing advice).

English blurs the two: "if it's cold, wear a jacket" and "when it's cold, wear a jacket" are near-interchangeable. Serbian is not blurred. Ask yourself whether the speaker treats the condition as doubtful (ako) or as something that regularly or certainly happens (kad). Kad je hladno, obuci jaknu — it gets cold every winter, so kad.

Order of the two halves

Either half can go first. Ako te boli glava, popij tabletu and Popij tabletu ako te boli glava say the same thing; the comma appears only when the ako-clause leads. The same holds for kad. In a question, the ako-clause usually comes second: Šta ćeš raditi ako sutra imaš temperaturu?

Keep to real conditions here: things that can still happen. The unreal kind — "if I were ill, I would stay at home" — uses a different construction that you will meet at the next level. Do not build it with ako plus bih.