语法笔记246题的两点疑问

gamxiaoyuan

Scientists have identified an asteroid, 2000 BF19, that is about half a mile wide and, if it strikes Earth, it can do tremendous damage to part of the planet but probably not cause planetwide destruction.
A. and, if it strikes Earth, it can do tremendous damage to part of the planet but
B. and, if it would strike Earth, part of the planet could experience a tremendous amount of damage but it would
C. and that, if it were to strike Earth, could do tremendous damage to part of the planet but would
D. and that, if Earth is struck by it, can do part of the planet tremendous damage, but it would  
E. and that, if it strikes Earth, it could experience a tremendous amount of damage but
这题的正确答案是C，但是我有两个问题想问：
1.语法笔记上说B的if条件句里的虚拟语气谓语形式错误，表示可能与将来事件相反,这句话是什么意思？为什么划线末端的it would...不存在这个问题？
2.and that...是和前面的that is about half a mile wide对应修饰asteroid的么？如果是的话and that后面加逗号再加条件状语从句可以这样修饰么？

jameshzd

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不是很确定哦。。 MM帮忙确认一下？


我只是觉得条件从句的时候，if I were you, i would go to bed earlier.  用would或者说will就挺平常，如果有can，或者could，就感觉不太像，呵呵。。。

-- by 会员 nemiah (2011/7/13 21:15:44)

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虚拟语气 是不会出现will 啊，肯定是用would。如果 原意是表达can 的话，虚拟中就用 could， 如果原意是 will 的话，那么虚拟语气中用 would。所以只有 if i were you, i would go to bed earlier.用 will就不对了。

nemiah

could也是可以用在虚拟语气的哦？

-- by 会员 nemiah (2011/7/13 21:10:02)

could 和 would 不是差不多可以互换吗？ 难道不是吗？ 我记得高中老师常常这样教导。。。

-- by 会员 jameshzd (2011/7/13 21:11:58)

不是很确定哦。。 MM帮忙确认一下？


我只是觉得条件从句的时候，if I were you, i would go to bed earlier.  用would或者说will就挺平常，如果有can，或者could，就感觉不太像，呵呵。。。

jameshzd

could也是可以用在虚拟语气的哦？

-- by 会员 nemiah (2011/7/13 21:10:02)

could 和 would 不是差不多可以互换吗？ 难道不是吗？ 我记得高中老师常常这样教导。。。

jameshzd

解释的太好了，跪谢！！！

-- by 会员 gamxiaoyuan (2011/7/13 21:08:14)

不用谢~~加油！！！感谢你今天给我发的逻辑英文帖子呢，帮我解决了大问题。

nemiah

could也是可以用在虚拟语气的哦？

gamxiaoyuan

解释的太好了，跪谢！！！

jameshzd

1：若虚拟语气表示与将来事件相反的话，从句 即if 句 后面的谓语形式是 were to do， 而主句是 would do，解释了后面为什么用 would。而前面要用were to do，用would 就错了。

2：是都是修饰asteroid， 你可以把 if 从句理解为插入语，来限定条件的。去掉 if 不看就是：an asteroid that is ...and that could... 其中 is 和 could 平行。
hope it helps~