In general, the tests work most effectively when the qualities to be measured can be most precisely defined.
一般来说，当所要测定的特征能够精确界定时，测试效果最佳。
In general, the tests work most effectively when the qualities to be measured can be most precisely defined and least effective when what is to be measured or predicted can not be well defined.
总体来说，当衡量的质量最精确时，测试是最有效的；然而，当无法定义衡量或测试的内容时，测试往往是无效的。
In general, the tests work most effectively when the qualities to be measured can be most precisely defined and least effectively when what is to be measured or predicted cannot be well defined.
总体来说，实验在可以最准确界定质量的情况下最为有效，反之，最无效。
In general, the tests work most effectively when the qualities to be measured can be most precisely defined and least effectively when what is to be measured or predicted can not be well defined.
一般说来，当需要测量的量能够准确界定时测试工作将更加有效，而当需要测量或预测的量不能被很好的界定的时候，测试工作就没那么有效了。
In general, the tests work most effectively when the qualities to be measured can be most precisely defined and least effectively when what is to be measured or predicted can not be well defined.
一般说来，当需要测量的量能够准确界定时测试工作将更加有效，而当需要测量或预测的量不能被很好的界定的时候，测试工作就没那么有效了。
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