知识要点1 contribute vi.&vt.促成，造成；捐献，捐助；是……的原因之一；增加，添加
(教材P48) Noise pollution and light pollution in big cities may also contribute to sleep problems.
大城市的噪音污染和光污染也可能导致睡眠问题。
[例1] Pollution from nearby factories has also contributed to the problem.
来自附近工厂的污染也是造成这一问题的原因。
