请将下面的单词按正确的发音归类.
问题描述：
请将下面的单词按正确的发音归类.
stpots rooms looks cars brushes maps walls watches oranges pens boxes trips bags buses cakes
/s/:________________________
/z/:________________________
/iz/:________________________
答
/s/ sports looks cars maps pens trips cakes
/z/ rooms walls bags
/iz/ brushes watches oranges boxes buses
walls和bags我拿不准