A section of a canal or a river that may be closed off by gates to control the water level to enable the raising and lowering of boats that pass through it.
While having breakfast with my parents, my dad looked up from reading the paper and said "I don't understand how this article says kids are getting dumber. I thought test scores and graduation rates are going up. How can this be?"
I then proceeded to tell my dad about the subject I know best--the NYS math A regents. I asked him what he thought the passing grade was. He said "When I went to school, it was 65." I told him it has been changed. "80?", he replied. My husband then chimed in "Not even close. To pass the Math A regents you only nee about 36 out of 85 points (or 42%) and you can get graduation credit with an even lower score."
It took a while for an 85 year old man to get the whole picture. He finally realized that education today is like being in a canal lock. You just lower the water level to let the boats pass through.