it在这两句中代替的是什么?这两句中weren't和hadn't been分别虚拟的有什么不同?

You wouldn't anywhere if it weren't for Ruth意思是：要不是有露丝(的帮助），你将不会有任何成就。 又如， 假定现在天气非常干旱，要是今后一周内不下雨，庄稼就会死掉，没发救了。 If there weren't any rain , the crops would die.in a week. 含if从句的虚拟语气表示对将来的虚拟时，If 从句中有三种谓语动词的形式1，动词的过去式，2，should +动词原形 3.were to do 所以上面句子可改为：If it didn't rain , the crops would die in a week if it shouldn't rain , the crops would die in a week if it weren't to rain ,the crops would die.in a week