文章中： Low levels of straying are crucial, since the process provides a source of novel genes and a mechanism by which a location can be repopulated should the fish there disappear. 哪位说说最后这几个词的语法是怎样的好么？不懂：（。。。谢谢：）
题目中也是一样的结构，猜得出意思，不知道语法关系：（
an environmentally degraded stream could be recolonized by new salmon populations should the stream recover
文章中： Low levels of straying are crucial, since the process provides a source of novel genes and a mechanism by which a location can be repopulated should the fish there disappear. 哪位说说最后这几个词的语法是怎样的好么？不懂：（。。。谢谢：）
题目中也是一样的结构，猜得出意思，不知道语法关系：（
an environmentally degraded stream could be recolonized by new salmon populations should the stream recover
虚拟语气:如果那里的鱼消失
A: 如果那里的河流恢复
有时if引导的状语从句可以省略 if，而把从句中的动词 were, had 或 should 移到主语前面
According to the passage, human activity has had which of the following effects on salmon populations?
A. An increase in the size of salmon populations in some previously polluted rivers B. A decline in the number of salmon in some rivers定位第一段Line 1-7 C. A decrease in the number straying salmon in some rivers D. A decrease in the gene flow between salmon populations that spawn in polluted streams and populations that spawn in pristine streams E. A decline in the vulnerability of some salmon populations to the effects of naturally occurring habitat destruction
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2004-9-26 19:58:00
楼主