When the organism dies, no new radioactive carbon is assimilated.

机体死后，不能再吸取新的放射性碳。

youdao

Non-radioactive carbon comes in two forms: 12C and the heavier (and much rarer form) 13C.

非放射性碳以两种形式存在：12C还有较重（并且更罕见）的13C。

youdao

A living organism would take in the radioactive carbon and convert it to organic material.

有生命的有机体会吸收具有放射的碳，并把它转化为有机物质。

youdao

4 And then there are the last four, carbon 14, which is a radioactive form.

然后，还有碳，以放射性形式存在。

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This would involve slipping a few radioactive carbon atoms into molecules of the drugs in question.

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As mentioned, carbon-14 is radioactive, and as the Sun becomes more active (interglacial times) so does the amount of the radioactive carbon-14.

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Because of the ratio of radioactive carbon and beryllium found in the tree rings, researchers could also rule out some other possibilities.

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