The letter "P" can make the "b" sound (the same sound in "bag"),when it is after sound "S" in the same syllable. eg. explore (iks-bloor), expensive(iks-ben-siv)
The letter "P" can also make the "P" sound (the same sound in "park"), when it is followed by consonants and after "s" sound in one syllable. eg. explore (iks-ploor), explain(iks-play-n)
When letter "P" is followed by vowels and after "s" sound in one syllable, it can only make the "b" sound (the same sound in "bag"). eg. expensive (iks-ben-siv), expand (iks-band)
Is that right?