在做高中數學時

在做 zaiˋ zuoˋ

(Doing, Working on) Doing, Working on

做高中數學 zuoˋ gaoˉ zhongˉ shuˋ xueˊ

(Did high, Do high, Does high, Doing, To do) To do high school math, Do high school math, Does high school math, Doing high school math, Did high school math

做高中數學時 zuoˋ gaoˉ zhongˉ shuˋ xueˊ shiˊ

(Doing) Doing high school math

高中 gaoˉ zhongˉ

(High school) High school

數學 shuˋ xueˊ

(Math) Math

數學時 shuˋ xueˊ shiˊ

(Math) Math time

學時 xueˊ shiˊ

(Class, Period) Class time, Period