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题库 / Prep2012-CR-30
In preparation for a large-scale tree-planting project, Thomasville has recorded the location, species, and condition of every tree in its downtown area. The results will be compared with results of the last such tree census, taken 20 years ago. Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now.
Which of the following, if true, most seriously undermines the claim that the tree-planting proposal will assure an abundant tree population?
Because of strict laws governing industrial development, environmental conditions in Thomasville are unlikely to become harsher for trees than they have been during the last 20 years.
Thomasville has reliable records to show which trees in existence 20 years ago were cut down to permit new construction downtown.
A number of trees from one of the species widespread in Thomasville 20 years ago reached the end of their natural life span in the intervening period.
Very few species of trees grow as well in urban conditions as in natural conditions.
A city with a high proportion of any one species of trees can have its tree population devastated by one outbreak of a disease.
原文：种在20年间有者best record的树；题目要求：undermine the claim(tree planting-->abundant tree population)
B选项，在20年前存在的树被砍了，无关
C选项：树到达了年龄生长极限，无关，也不能说明claim
E选项：只种单一数目的树，可能会使得树由于某种疾病而大量死亡，因此不会有abundant tree population，可选
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