He wouldn’t have been saved even if he___________(send) to hospital at once.
问题描述：
He wouldn’t have been saved even if he___________(send) to hospital at once.
答
had sent
虚拟语气，很明显，if后面陈述的与现实情况不相符合，所以必须用虚拟语气，借以表示自己某种情感。
答
he had been sent to hospital at once.
虚拟语气，就算他被立马送到医院，也不会被救活的。
都是讲的以前发生过的事情，所以用的would have done.+ had done表示。
而这里他是被送的，不是自己走去的，所以要用被动语态。
答
had sent
虚拟语气,(even )if + 主语 had+ 过去分词,主语 + would have + 过去分词
翻译：即使立即送他去医院,也不能挽救他的生命
答
sent
用过去式，因为主句wouldn't have been saved是虚拟语气，所以从句用过去式，send的过去式是sent
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