Listen and read.
[ə]
teach$\mathbf{\text{er}}$
comput$\mathbf{\text{er}}$
sharpen$\mathbf{\text{er}}$
answ$\mathbf{\text{er }}$
 
[e]
p$\mathbf{\text{e}}$ncil
d$\mathbf{\text{e}}$sk
l$\mathbf{\text{e}}$sson
qu$\mathbf{\text{e}}$stion
t$\mathbf{\text{e}}$xtbook
 
[u:]
sch$\mathbf{\text{oo}}$l
r$\mathbf{\text{u}}$ler
t$\mathbf{\text{wo}}$
 
[ʊ]
b$\mathbf{\text{oo}}$k
textb$\mathbf{\text{oo}}$k
workb$\mathbf{\text{oo}}$k
l$\mathbf{\text{oo}}$k
p$\mathbf{\text{u}}$t