lead to

cause, origin, source, principle, element; occasioner, prime mover, primum mobile; vera causa; author (producer); mainspring; agent; leaven; groundwork, foundation (support)., spring, fountain, well, font; fountainhead, spring head, wellhead; fons et origo, genesis; descent (paternity); remote cause; influence., pivot, hinge, turning point, lever, crux, fulcrum; key; proximate cause, causa causans; straw that breaks the camel's back., ground; reason, reason why; why and wherefore, rationale, occasion, derivation; final cause (intention); les dessous des cartes; undercurrents., rudiment; egg, germ, embryo, bud, root, radix, radical, etymon, nucleus, seed, stem, stock, stirps, trunk, tap-root, gemmule, radicle, semen, sperm., nest, cradle, nursery, womb, nidus, birthplace, hotbed., causality, causation; origination; production.

be the cause of; originate; give origin to, give rise to, give occasion to; cause, occasion, sow the seeds of, kindle, suscitate; bring on, bring to bring pass, bring about; produce; create; set up, set afloat, set on foot; found, broach, institute, lay the foundation of; lie at the root of., procure, induce, draw down, open the door to, superinduce, evoke, entail, operate; elicit, provoke., conduce to (tend to); contribute; have a hand in the pie, have a finger in the pie; determine, decide, turn the scale; have a common origin; derive its origin (effect).

caused; causal, original; primary, primitive, primordial; aboriginal; protogenal; radical; embryonic, embryotic; in embryo, in ovo; seminal, germinal; at the bottom of; connate, having a common origin.

because; behind the scenes.

timeliness, occasion, opportunity, opening, room; event (eventuality); suitable season, proper season, suitable time, proper time; high time; opportuneness; tempestivity., crisis, turn, juncture, conjuncture; crisis, turning point, given time., nick of time; golden opportunity, well timed opportunity, fine opportunity, favorable opportunity, opening; clear stage, open field, window of opportunity, fair field; mollia tempora; fata Morgana; spare time (leisure).

seize (take) an opportunity, use [more] an opportunity, give [more] an opportunity, use an occasion; improve the occasion., suit the occasion (be expedient)., seize the occasion, strike while the iron is hot, battre le fer sur l'enclume, make hay while the sun shines, seize the present hour, take time by the forelock, prendre la balle au bond.

opportune, timely, well-timed, timeful, seasonable., providential, lucky, fortunate, happy, favorable, propitious, auspicious, critical; suitable; obiter dicta.

opportunely; in proper course, in due course, in proper season, in due season, in proper time, in due time; for the nonce; in the nick of time, in the fullness of time; all in good time; just in time, at the eleventh hour, now or never., by the way, by the by; en passant, a propos; pro re nata, pro hac vice; par parenthese, parenthetically, by way of parenthesis, incidentally; while speaking of, while on the subject; extempore; on the spur of the moment, on the spur of the occasion; on the spot (early).