★if引导的条件从句中包含有were,had,should或could时，可将if省略，但此时要将were,had,should或could放在主语前面（这种结构在口语中较少使用）：

★实战演练：

If he were ill,I would take care of him.

=Were he ill,I would take care of him.

他若生病，我会照顾他。

If he had learned about the result,he might have been angry.

=Had he learned about the result,he might have been angry.

他当时要是知道这结果，也许会生气。

If he should stop helping me,my plan could be ruined.

=Should he stop helping me,my plan could be ruined.

万一他不再帮助我，我的计划就要泡汤了。

If the dead man could have spoken,he would have identified his murderer.

=Could the dead man have spoken,he would have identified his murderer.

如果死人会说话，他会认出谁是谋害他的人。