2. 专升本
  3. It takes a long time to grow a tree. How long? Well, pine trees are the quickest growing trees, but still, they take twenty year

It takes a long time to grow a tree. How long? Well, pine trees are the quickest growing trees, but still, they take twenty year

admin2011-06-28  53
问题     It takes a long time to grow a tree. How long? Well, pine trees are the quickest growing trees, but still, they take twenty years to reach a size suitable for cutting and harvesting. An oak takes about sixty years to grow to a good size. A redwood may take hundreds of years.
    Lumber companies, which make their money on trees, depend on those that grow quickly. There- fore, they are always looking for methods to make trees grow faster. So far, the secret to fast growing trees seems to lie in "super-seeds." These are seeds that are gathered from the quickest growing trees in a forest.  One company searched 100,000 acres of trees and selected the seeds from just fifteen trees. These two ounces of seed were enough to plant several hundred new trees.  Eventually, when these trees have grown, seeds will again be taken only from the fastest growing trees of crop. This process of artificial selection will yield, in the future, a super-tree that will grow in half the time it takes normal trees to develop.
    Unfortunately, it takes a long time for a plan like this to reach its goal. The Weyerhauser Lumber Corporation, which started its first collection of seed in 1958, is just now beginning to harvest the super-seeds of the first generation of the faster growing trees.
Trees that grow faster are developed by ______.
选项 A、planting many trees and fertilizing them
B、collecting seeds from strong, slow growing trees
C、selecting the seeds of the fastest growing trees
D、feeding them high-energy plant foods
答案C
解析 第二段。文中提到超级种子。从很多树中选出15棵长得最快的树，获得他们的树种，再种，再从中找出长得最快的树的树种，再种。以此类推，就可获得成材快的树木了。所以是靠超级种子达到长得：陕这一目的的。选项C是正确的。
转载请注明原文地址:https://www.kaotiyun.com/show/QJlC777K
本试题收录于： 英语题库成考专升本分类
0

英语

成考专升本

相关试题推荐
随机试题
最新回复(0)