grammar → 只要…就…
TSUMUGU · TBCL 3 (est.) · 語法
只要…就… grammar point · tier 2 · 只要…就… as long as / so long as (sufficient condition → then)
Sufficient condition: this one thing is all it takes, and then the result follows.

字源 FORM what the parts do

只 carries only (a meaning the graph took on loan) — it pins the condition to this one thing; 要 says that one thing is what it takes; 就 fires the result the moment it is met.

故事 STORY a scene to remember it by

One low bar set across the path; clear that single bar and the gate ahead is already open.
自撰字源記憶法
框 · Frame
只要 [the one sufficient condition],就 [result]
觸 · Trigger
You want to name the single condition that is enough on its own to bring the result — nothing more is asked.
序 · The move
1Put the one condition that suffices after 只要.Is this genuinely all it takes, with nothing else required? If other conditions are needed too, 只要 is wrong.
2Open the result clause with 就.Does the result follow whenever that single condition holds?
3Keep the subject in front of 就 or 只要, not between 就 and the verb.就 sits right before the verb of the result.
例 · Examples
1只要as long as / so long as有空have free timethenwill參加attend, take part in這次的派對party
As long as he has time, he'll go to the party.
界 · Boundary
如果…就…
如果 lays out one possible condition among others (if it happens); 只要 declares that condition sufficient on its own (this much alone is enough).
只有…才…
只要 = this is enough, the result follows (sufficient, low bar); 只有…才… = nothing else will do, only this unlocks it (necessary, the sole key). Swap 就 for 才 to flip enough into only-then.
✗ 只要他有空,他才去。 → ✓ 只要他有空,就去。 (sufficient condition takes 就, not 才)
✗ 只要下雨,我去。 → ✓ 只要下雨,我就去。 (the result clause needs 就)
✗ 如果你努力,就一定成功。 → ✓ 只要你努力,就一定成功。 (use 只要 when the one condition is presented as enough on its own)
English as long as covers both 只要 (sufficient) and time-span duration; 只要 is conditional sufficiency only, never how long something lasts.