Thus, you can picture development as a chain of revisions, where each revision builds on the changes captured in its parent.
因此，可以把开发过程看作由修订组成的链条，每个修订基于其父修订中包含的更改。
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Nowhere are theseissues better exemplified than in the Himalayas, the 2400-km-long chain ofmountain ranges stretching between the Indus and the Brahmaputra River valleys(see the picture, above).