According to some botanists, invasive plants are the second most serious threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems.

A. threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems

B. threat, after habitat loss, to native species of plants and animals and for maintaining biologically diverse ecosystems

C. threat, after losing their habitat, to native species of plants and animals and also to maintenance of biologically diverse ecosystems

D. threat to native species of plants and animals and for maintaining biologically diverse ecosystems, after habitat loss

E. threat to native species of plants and animals as well as to maintaining biologically diverse ecosystems, after losing their habitat

答案是A 考虑平行并列to……and to……我能理解，

但是species能和抽象名词maintainance并列么？

还是我想太多了~？

确实不必考虑。重点在于两个介宾短语的平行。介宾短语的宾语无论是抽象名词还是

实意名词都无所谓

确切的说就是介宾短语的宾语的对称不用强调具体和抽象的对称是吗？

因为有些其他状况还是有考到 具体 和抽象 对称 错误的问题。

不过如果有这一点的话就明白多了。：）

说起来这个对称问题也不是语法之外的。。。

呃~~ 具体不对抽象，抽象不对动名词，特指不对泛指，这些也是语法的考点吧。

不过可能这题我是有点钻牛角尖了……

唉……我总犯这种毛病 不知道怎么办……