好奇怪的虚拟条件语句啊 小女子求各位武林高手指教~~

原句正常的语序应为：if green plants should disappear some day,...should在这里表达将来，句子是针对未来的虚拟，这样的句子should可以提前，同时去掉if，表示强调should... you come to my birthday tonight, everythings would be more interesting这种结构也会出现在另一个句子中，如：if i were you, i wouldnot say so. were i you, i would not say so.（只有这两种）联系上下文，后面同样应是对未来的虚拟。译文：如果有一天所有的绿色植物都消失了，地球上也就不会再有任何生命。