ch但是发音要是 /shi/,可是楼主的举例 lunch 中的 'ch' 不发 /shi/的音,而是发 /chi/ 的音.
sh 发/shi/的音有很多,如:
sheep sheet shape shoot shot show dish fish shy shop
share shoe cash trash she shell Washington wash Welsh
dash splash cash rash rush shark fresh brush sunshine
shame wish shrimp shade perish push shout
ch 先说发 /shi/的音,如:
chagrin Chicago parachute moustache machine Michigan brochure chauffeur chaise chalet
champagne chambray chamois chandelier chapeau chaparral chaperone charade charlatan
Charlotte chauvinist chef chemise chevron chiffon chivalry chute cache crochet
ch 发 /chi/的音也很多,如:
china cheap chip cheat teach kitchen chicken peach reach
breach chat champion chew crunch brunch French check chain chair charming chase chalk child chilly chief touch search which launch 等