So where does this constraint, you may think it's a fairly minimal constraint, but where does it come from?

你可能觉得这些制约相当微小，但它从何而来呢？

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The gadget does share a constraint common to all satellite-connected gear: Line of sight to the sky is required for connectivity.

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That constraint would ensure that the national debt does not rise as a share of national income unless an extraordinary majority in Congress deems that it should.

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