Subsutitude teacher - Dec 4th (99)

Today, normal teacher doesn't come so other teacher did come and teach us.
In that class, we have 2 period. first teacher just impose us on simple task and wait for time passed. we don't feel comfortable because it was waste of time.
However, next teacher taught me a lot. For instance, importance of clausing noun and position. it was very useful and meaningful information for me.

Why class quality depends on teachers? I pay for same amount of money for language school but actually, they don't treat us as the same. I think it should be decrease because of equality and nessecity.