单语范例（未经PONS编辑处理）
Because some of the water sources flow through populated areas or farms, water sources along the trail may be unfit to drink.
en.wikipedia.org An original source is one that is not based on another source.
en.wikipedia.org Any other sources he used, if any, are unclear.
en.wikipedia.org However, they could have benefited from new teachers or an additional source of funding in order to pay teachers already on staff.
en.wikipedia.org Some proctoscopes have a light source for better visibility.
en.wikipedia.org