Pollutionis the price we pay for an overpopulated, over industrialized planet.
Whenyou come to think about it, there are only four ways you can deal withrubbish: dump it, burn it, turn it into something you can use again,attempt to produce less of it.
Wekeep trying all four methods, but the sheervolume of rubbish we produce worldwide threatens to overwhelm us.
1）When youcome to think about it -这个it应该是指"Pollution"吧？书上翻译成“当大家开始考虑垃圾问题时” -垃圾？是不是错误呢？这个sheer可以用强调的very,only,alone替换吗？
2）there areonly four ways you can deal with rubbish - 感觉句子缺少成分？应该是 there are only fourways you can deal withrubbish ？
1 这个it应该指rubbish。假如只pollution，后面句子就与状语前言不搭后语了，由于pollution不仅仅是垃圾，还有水污染、空气污染。你可以理解这个it是前照应指代，指代后面的rubbish。sheer在此为强调意义，英文解释为：used to emphasize the large amount, size, or degree of something。不要替换，你就老老实实的学习sheer在此的使用方法和意义，不然你永远不了解怎么样用sheer。词典例句：
The sheer amount of work was staggering.
2 句子没问题。You can deal with rubbish in four ways. 你感觉这个句子有问题吗？