prep1-124 if从句的内容对吗

124.      (31091-!-item-!-188;#058&004372)

Whereas the use of synthetic fertilizers has greatly expanded agricultural productivity in many parts of the world, an increase in their use can create serious environmental problems such as water pollution, and their substitution for more traditional fertilizers may accelerate soil structure deterioration and soil erosion.

(A) an increase in their use can create serious environmental problems such as water pollution, and their substitution for more traditional fertilizers

(B) an increase in their use can create serious environmental problems like water pollution, and if substituted for more traditional fertilizers, it　　

(C) if these fertilizers are used increasingly, they can create serious environmental problems such as water pollution, and if used as substitutions for more traditional fertilizers, they

(D) the increased usage of these fertilizers can create serious environmental problems such as water pollution, while if substituted for more traditional fertilizers, this substitution

(E) the increased usage of these fertilizers can create serious environmental problems like water pollution, while their substitution for more traditional fertilizers

BCD中的        if substituted...if used...有没有问题，感觉这个如果是省略的主语了

C好像没啥明显错误啊

我觉得B,C,D中：if + 过去式，表达了一种非真实条件了，好像是不可能实现的一样

C中第一个they，指代错误，应该是那个使用肥料的过程造成污染，也就是像A所说的use造成了污染。

如果表达一种不可能实现的，应该用虚拟了，这里也没有用虚拟阿

那你通过别的方式去除错误选项。　Ｂ，Ｅ错在举例用like,　可以排除。Ｄ中substituted for 和 substitution啰嗦。　Ｃ中语气不对，句子想表达是转折含义，但Ｃif表示了假设。。。如果。。。的含义。所以在ＧＭＡＴ中对于if 的出现我觉得一定要用语气来看是否对。

昨晚脑子不清楚，确实没用虚拟...只是省略了主语和be动词

if substituted for more traditional fertilizers这个用法是对的,只是第一跟前面不平行对称，第二后面的主语it，they指代不清。

这个要看状态，我觉得有时候一眼看到就知道了...

你像化肥不去用怎么会污染环境呢...棒子也是要乱丢才会砸到花花草草的