gwd1 Q9-12

brunhildS

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。
请问这句话的后半句.by which a location can be repopulated should the fish there disappear 怎么翻，should在这里起什么作用什么意思？真的看不懂。谢谢大家！

xiangxiangling

我觉得should表示的是有可能的意思

poorleafes

这里的should引导的倒装结构是表虚拟语气，表示“一旦。。。”或者“假如。。。”的意思。

假如某location那里的鱼完全消失，之前提到的那些走散的鱼所携带的基因也能够让这个location的鱼重新繁殖。

brunhildS

谢谢你哦，这个语法知识点我怎么从来没有看见过呢？

poorleafes

语法虚拟语气 虚拟条件句的倒装

虚拟条件句的从句部分含有were， should， 或had时， 可省略if，再把were， should或had 移

到从句的句首，实行倒装。例如：

　　Were they here now， they could help us. =If they were here now， they could help

us.他们现在在的话，就会帮助我们了。

　　Had you come earlier， you would have met him. =If you had come earlier， you

would have met him.你来得早一点，就碰到他了。

　　Should it rain， the crops would be saved. =Were it to rain， the crops would be

saved.假如下雨，庄稼就有救了。

注意：在虚拟语气的从句中，动词'be'的过去时态一律用"were"，不用was，即在从句中be用were

代替。例如：

　　If I were you， I would go to look for him. 如果我是你，就会去找他。

　　If he were here， everything would be all right. 如果他在这儿，一切都会好的。