请教几题SAT语法~1.【From】 about 700A.D to 1600,sculptors 【created】

请教几题SAT语法~
1.【From】 about 700A.D to 1600,sculptors 【created】 【nearly】 1000 colossal statues rock on the 【remote】 and tiny Easter Island.答案是no error,为什么created没错?不是应该用had created么?
2.The newspaper business in the United States faces a 【challenge,being that it must reconcile the high-minded goal of informing readers with the commercial one of making money】
答案是：challenge because it must reconcile the high-minded goal of informing readers with the commercial one of making money
为什么不能选 challenge of it reconciling the high-minded goal of informing readers with commercial one of making money?
3.【As】 children mature, they develop 【an independence】 that their parents, who 【have been】 responsible for them since they were born, often find difficult 【to accept】 答案是no error,为什么an independence没错?不是不可数么?
4.【Along】 the curve of islands known as the Florida Keys 【lies】 a reef of living coral,【the only one】 of 【a kind】 in the continental United States.答案是【a kind】 这里a kind 虽然有些别扭 但是具体错在哪里?
5.【If we compare the number of alligators with the Gila monster over time, we see that the alligator is】in decline.
答案是：A comparison over time of the number of alligators and Gila monsters shows that alligators are
为什么不能选：Comparing the number of alligators and the Gila monster, we see that alligators are
6.Unfortunately, the opening of the new library complex, 【previously】【scheduled for】 next September,【would be】delayed for several months 【because of】construction difficulties.答案是【would be】是不是因为要改成will be?那would be 能不能理解成是过去完成时呢?
7.In Germany, foresters discovered that trees killed by acid rain had begun to die four years 【earlier, even though the trees had shown no signs of disease then.】
答案是选原句,为什么不能选【earlier without any signs of disease shown then.】?我觉得这个更简洁而且没什么错..

1,没有明显的过去的先后时间对比,就不要用过去完成时.题中已经明确了过去的那段时间.
2 你选的那个语法就不对,of 后面是想解释什么挑战,但是后头的句子用it ……都混乱了.
3 当独立性讲时是可数的.
4 把 a 去掉
5 短语是 compare A with B
6 是应该改成will be ,would be是想误导考生,不能因为前面有个scheduled 就觉得应该把will 改成would,scheduled是过去分词做定语用来表示被动关系,跟时态无关,因为新图书馆的openning不能主动发出动作,所以是被计划.
7 even though 更能体现出句子间的逻辑关系,你想选的那句则混为一谈,虽然意思对,但体现不出句式关系,表达出来的意思就会有差别.
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