旧prep 101 ?

futureflow

101.    (29937-!-item-!-188;#058&004052)
Many environmentalists, and some economists, say that free trade encourages industry to relocate to countries with ineffective or poorly enforced antipollution laws, mostly in the developing world, and (that, in order to maintain competitiveness, rich nations have joined this downward slide toward more lax attitudes about pollution.   )
(A) that, in order to maintain competitiveness, rich nations have joined this downward slide toward more lax attitudes about pollution
(B) that, for maintaining competitiveness, rich nations join in this downward slide toward more lax attitudes about pollution
(C) that rich nations join this downward slide toward more lax attitudes about pollution because of wanting to maintain competitiveness
(D) that in rich nations, joining this downward slide toward more lax attitudes about pollution is a result of wanting to maintain competition
(E) that wanting to maintain competition is making rich nations join in this downward slide toward an attitude about pollution that is more lax
答案是A，请教为什么用完成时呢？？？？
B有什么不对呢？虽然for doing没有to do 好， 但是在不确定时态的情况下，就选了B

shanjun0888

是不是因为没有join in这个用法呢？。。。我不记得join后面需要加介词。。。。

luopite

这里环境学家和经济学家讲的是一个事实，也就是说的是一件已经发生的事情。富裕的国家为了保持竞争力，表示一种目的，所以后面从语义上来说一定是富裕国家已经joined this downward slide 从而达到了目的。
有in order to do的情况下，还没见过哪题是选for doing来表目的