如果…就

如 rú (to be like; to match; to follow) + 果 guǒ (fruit; result; indeed). 如 originally depicted a woman kneeling before a mouth — speech conforming to another's. 果 shows a tree bearing fruit — the natural outcome of growth. Together: "if [this condition] indeed comes to pass" — if indeed, supposing.

就 jiù is one of Mandarin's most versatile words — it marks: the consequence of a condition, immediacy ("right away"), or limitation ("just/only"). As a consequence marker, 就 picks up where 如果 leaves off: the condition having been granted, 就 says "then and only then." It ties the result tightly to the premise.

Chinese conditionals are structurally similar to English "if…then" but with a crucial difference: 就 is an adverb that sits before the verb in the consequence clause, not a conjunction. Understanding this prevents learners from omitting it or placing it in the wrong position.

就 jiù is doing heavy grammatical lifting in this construction. As an adverb, it precedes the verb in the consequence clause and means "then and in that case." It signals: the condition having been met, this result follows naturally and directly.

Importantly, 就 can appear even without 如果: 你早点来，我就早点走 (if/when you come earlier, I'll leave earlier). The condition-result relationship is implied by the sequential structure alone. 就 marks the result. This means that in spoken Mandarin, learners frequently drop 如果 while keeping 就 — and that's grammatically valid.

Be aware: 就 has many other uses (just; only; right away; as early as). In the conditional frame it is specifically a consequence marker. The context — a prior condition clause — is what signals its conditional function.