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标题: a LR question [打印本页]

作者: chasingd2012    时间: 2012-1-5 12:06
标题: a LR question
原题是: Mature white pines intercept almost all the sunlight that shines on them. They leave a deep litter that dries readily, and they grow to prodigious height so that, even when there are large gaps in a stand of such trees, little light reaches the forest floor. For this reason white pines can't regenerate in their own shade. Thus when in a dense forest a stand of trees consists of nothing but mature white pines, it is a fair bet that_____

Which one of the following most logically concludes the argument?

正确选项是(A): the ages of the trees in the stand don't differ from each other by much more than the length of time it takes a white pine to grow to maturity.

但不太明白这个选项为什么对,是怎么一个关系?
作者: simonshen    时间: 2012-1-5 12:18
这题的题目里说mature 的white pine会阻挡住阳光,并且长得很高,因此使得树林的低矮处见不到阳光,因此如果white pine长在一起的话肯定都是差不多同时栽下去,同时成熟长高的。因为如果在一起的white pine,先种一些让他们成熟,他们就会长得很高遮住阳光,然后在这些树木成熟后,再新种的white pine因为很矮,在低处就得不到阳光不可能生长了。所以如果white pine种在一起的话,他们之间树龄的差距应该不会大于其中一些树长成年的时间。




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