18. Supply pairs of words which can be distinguished by the following sets of sounds, e.g. for /p/ and /b/ post and boast.

Sound PairWord Pair
/p/ & /b/
/t/ & /d/
/k/ & /g/
/f/ & /v/
/θ/ & /ð/
/s/ & /z/
/s/ & /θ/
/z/ & /ð/