For the children, junior high also serves two purposes. These two years are set aside for remedial work, so if your child needs extra help in math, or writing, that's what this time is for. You can't be behind, because the purpose of 7th and 8th grade is to spend time getting those skills up to grade level. The other purpose of junior high is to allow children to take high school level classes in any areas where they are ready. If they are ready for Algebra 1 or French 1, then they can take those high school level classes (and you can put it on the transcript) even if they are doing remedial work in other subject areas.
So you see, it's not possible to be "behind" or "ahead" in junior high, because the purpose is to serve both needs.

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