1. Even if a piped water supply is safe at its source, it is not always safe by the time it reaches the tap.
    即使管道供水系统在水源处安全的，等水到达龙头时就不一定总是安全的了。

2. We must trace the source of these noxious gases before they asphyxiate us.
    在我们被这些有毒气体窒息之前, 必须查出其来源。

3. Where is the source of the Thames?
    泰晤士河源出何处？

4. Whatever the source of noise, one thing is certain: silence, it seems, has become a golden memory.
    不管噪声来自何方，有一点是肯定的：看来寂静已变成一种珍贵的回忆。

5. Water is the source of this beauty and the source of life on Earth.
    水是地球上的美丽之源、生命之源。

6. Women of child-bearing age are at greatest risk, since their monthly bleeding is a major source of iron loss.
    育龄女性危险最大，因为月经是铁流失的重要原因之一。

7. Travellers on short trips to areas with water supplies of uncertain quality should avoid drinking tap-water, or untreated water from any other source.
    短途旅行到水质不保险的地区时，应避免饮用水龙头的水或未经处理任何其他来源的水。

8. The noise pollution survey revealed a rather surprising and possibly amusing old fashioned source of noise.
    这个有关噪音的污染调查还揭示了一种出人意外而同时可能会引人意外而同时可能会引人发笑的老式噪音源。

9. Then she left England for Africa, the source of what was called "the black gold."
    然后该船离开了英国前往非洲，那里被称作“黑色黄金”的源头。

10. The continual source of our strength was our mutual trust and respect.
    相互信任和尊重是我们俩永不枯竭的力量源泉。