โ = o
เ-อ = er
เ-อะ = er (should use sound shortest) like d, t, n (pin yin)
-----------------
โ -ะ
เ- าะ
^
^
No have this sound in Chinese
But when you will pronounce โ-ะ (O) You should use sound shortest
โ-ะ (O) shortest not โ (o)
like... b p m f (pin yin) ^_____^
เ- าะ = or (use sound shortest)