关于虚拟从句的倒装问题

问题描述:

关于虚拟从句的倒装问题
If you had not helped me,I should have failed.
要是没有你的帮助,我就失败了.
可以改为
Had you not helped me,I should have failed.
那么可以把虚拟从句放在主句背后吗:
I should have failed,had you not helped me.

If you had not helped me,I should have failed.
要是没有你的帮助,我就失败了.
可以改为
Had you not helped me,I should have failed.
可以把虚拟从句放在主句后面:
I should have failed,had you not helped me.
但是一般是放在前面的.