If I got it right, you can't shift down to the middle chain ring when in 3 smallest rear cogs.If it is the case, it is not normal. My guess is, the front derailleur is not installed properly(possibly, the cage is not parallel to the chainrings). There may be other causes too.
Look here for the tutorial : http://www.utahmountainbiking.com/fix/
enter the "Derailleur, front replacement" and "Derailleur, front, tune".
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