It has three parts - submarines, missiles and warheads, and although each component has years of use left, they cannot last indefinitely.

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It has three parts: planning, more planning and still more planning.

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The official German defence has three parts, broadly, and it unites the centre left and centre right wings of the coalition government.

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The chemical, one part nitrogen to three parts hydrogen, stores a lot of energy: a gallon of it has about half the Btus as a gallon of diesel.

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