It is not that...but that...  这不是说……，而是说……
    例1: It is not that the scales in the one case, and the balance in the other, differ in the principles of their construction or manner of working; but that the latter is much finer apparatus and of course much more accurate in its measurement than the former.
    译文：这并不是说在一种情况下所使用的磅秤和另一种情况下所用的天平在构造原理上或工作方式上存在差别，而是说与前者相比，后者是一种更精密得多的装置，因而在计量上必然更加准确。
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