st、sk、sp st、ｓk、sp在重音里时要变音; st、ｓk、sp词首变音，词尾不变音； 变音：skate　，　skill，　square　，　stand　，　sport　，　speak　，　study　 不变音:interesting　，　inspiring 浊化对应 S后加清辅音，必须重读[......] 继续阅读

st, sk, sp When stressed, st, sk, and sp undergo sound changes; At the beginning of words, st, sk, and sp change their sound, but at the end of words,[......] 继续阅读