ph
ph = /f/
Initial position(首):phonic, phonics, photo, photograph, phone, microphone, phony, phobia, phase, phrase, phoenix, physics, physical, physician, phishing, phew, pharmacy, phosphorus, philosophy, phenomenal, phenomenon
Medial position(中):alphabet, alpha, elephant, emphasis, emphasize, hyphen, nephew, symphony, biography, geography, demography, calligraphy, catastrophe, graphite, graphic, pamphlet, telephone, camphor, metaphor, cipher, sulphur, asphalt, prophecy, trophy, periphery, peripheral, dolphin, orphan, siphon, sapphire, sphere, atmosphere, sophisticate
Final position(尾):graph, paragraph, autograph, triumph, morph, oomph, humph