Being caused by pollution, the water in the river cab't be drunk any longer

由于受到污染,河里的水已经不能再喝了

句子主干 the water can't be drunk 水不能被喝
any longer 做状语修饰前面,指时间上,不再
in the river 介词短语限定前面的water
Being caused by pollution ,针对后面的water ,指水不能喝的原因（是由于被污染），属于现在分词短语作原因状语

因为亏染，河里的水已经不能再饮用了

由于被污染，河里的水已经不能再饮用了。

中意:由于污染,河里的水已经不能再喝了

句子主干 the water can't be drunk 水不能被喝
any longer 修饰前面,指时间上,不再
in the river 介词短语限定前面的water
Being caused by pollution ,针对后面的water ,什么被污染,水被污染

Being caused by pollution, the water in the river can't be drunk any longer

这句中
主语是the water 谓语是 be drunk 被动语太

Being caused by pollution是这里是现在分词引导做原因状语

in the river 修饰 the water 这里是介词短语坐位定语

not......no longer是一个词语 表示：再也不能.....的意思