Electrical circuitry make me sad~

Yesterday I though that I give back my electronics and electrical circuitries to teacher ,
a simple circuitry that combines the Pre-amplifier and 2-nd order active order low pass filter
spend my all three work days , god !! I am so sad ..... but in this process I learn some knowledges
first one when single circuitry is tested completely, you must consider the effect which circuitries
provide ! Likes as frequency response , gain, and other characteristics of system. I regret that I am a bad student formerly ,because I always play and talk with my classmates in experiment ,I don't train myself at the time ~ ha ha~ So basic knowledge is very important ! Sometimes some problems are solved by the basic , don't have to use more difficult technique ~
Finally I wish everybody will be more professional in your area!!