spontaneous

a.自发的；自动的

spoils system, spoke, spoken, spokeshave, spokesman, spokeswoman, spoliation, spondaic, spondee, sponge, sponge-bag, sponge-cake, sponge-pudding, sponger, sponginess, sponging, spongy, sponsor, sponsorship, spontaneity, spontaneous combustion, spontaneously, spoof, spook, spookiness, spooky, spool, spoon, spoon-feed, spoonerism, spoonful, spoor, sporadic, sporadically, spore, sporran, sport, sportily, sportiness, sporting,