| 1. | Automobile exhaust gases are considered the major source .
据认为汽车排出的废气是主要来源。 |
| 2. | The fishing industry was a primary source of colonists' wealth .
捕鱼业是殖民者财富的主要来源。 |
| 3. | The three main sources of power are coal, oil and water power .
动力的三个主要来源是煤，石油和水力。 |
| 4. | One or two staple crops are the chief sources of food intake .
一、两种主要农作物是人们食物的主要来源。 |
| 5. | Incomplete combustion is the principal source of man-made carcinogens .
不完全燃烧是人为致癌物的主要来源。 |
| 6. | Hydrogen to helium conversion provides the prime source of energy for stars on the main sequence .
由氢向氦的转变是主序星能量的主要来源。 |
| 7. | A major portion of the soil organic matter is derived from the added and residual vegetative material .
加进去的和残留下来的植物物质则是土壤有机质的主要来源。 |
| 8. | Tritium is radioactive and is believed to be the main source of the major traces of 3he found in the atmosphere .
氚是放射性的，并且确信是大气中痕量3He的主要来源。 |
| 9. | The major sources of the material in this work can generally be identified despite our slim knowledge of the classical period .
书中材料的主要来源一般都能查到，尽管我们对古典时期所知甚少。 |
| 10. | When helium burning takes over the main burden of energy generation in the star, the core expands somewhat, and the envelope contracts somewhat .
当氦燃烧成为星体能量产生的主要来源时，核心略微膨胀，而包层略微收缩。 |
