由重'磅(7.2千克)的金属球和一条长链或木把手组成，人手持链端或把手在田径比赛中将其投远以争高低。

Sports a metal ball weighing 'pounds (7.2 kilograms) and having a long wire or wooden handle by which it is thrown for distance in track-and-field competition.

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链球由重16磅(7。2千克)的金属球和一条长链或木把手组成，人手持链端或把手在田径比赛中将其投远以争高低。

A metal ball weighing16 pounds (7. 2 kilograms) and having a long wire or wooden handle by which it is thrown for distance in track - and - field competition.

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然而体积大重量重是背投系统致命的弱点，系统厚度和质量也是衡量背投系统实用性的重要指标。

Whereas, the large volume and heavy weight are fetal to the system, which are crucial factors to evaluate it.

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