| 1. | 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。 |
| 2. | 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。 |
| 3. | This would involve slipping a few radioactive carbon atoms into molecules of the drugs in question
这涉及到将很多放射性碳原子放入药物分子中的问题。 |
| 4. | The radioactive carbon atoms weigh 14 atomic units , whereas run - of - the - mill ones weigh 12 units
这种放射性的碳原子为14原子单位，而普通碳原子为12原子单位。 |
| 5. | The technique is so sensitive that it can detect a single radioactive carbon atom hiding among a quadrillion ( one million billion ) ordinary ones
这项技术非常敏感，甚至能够在十的十五次方（一千万亿）个普通碳原子中找到一个放射性碳原子。 |
| 6. | Using carbon - dating techniques , archaeologists can determine the age of many ancient objects by measurement the amount of radioactive carbon they contain
参考译文：在太阳深处的内核中，氦和氢经过一系列高热原子核反应熔合作用产生了太阳的能量。 |
| 7. | Food grains , scraps of cloth , bits of wood and so on can thus be dated by finding out how much radioactive carbon is left in them : the less there is , the older they are
食用的谷物、衣物的脱屑、少量木屑等等都可以通过计算放射性碳含量而得知他们距今有多久：含量越少，年代越久远。 |
| 8. | Calvin , melvin ( 1911 - 97 ) american biochemist noted for his investigations of the dark reactions of photosynthesis ( using radioactive carbon ) . he was awarded the 1951 nobel prize for chemistry
卡尔文：美国生物化学家，他使用放射性的碳原子发现了在光合作用中的暗反应。 1951年他被授予诺贝尔化学奖。 |
