For my non-native-English-speaking readers, the following "tongue twister" (which I, and just about everyone I knew as a child, learned as children) may help illuminate why my last posting makes any sense at all:
Peter Piper picked a peck of pickled peppers. If Peter Piper picked a peck of pickled peppers, where are the pickled peppers Peter Piper picked?
(A peck is an amount, or in other words a volume you can pick, like a cup or a bushel or a liter. No, you can't really pick pickled peppers; the whole point of the sentence is that it's hard to say fast, and makes little children giggle when they try to do so.)