the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally. The Egyptians, however, did not discover leavened bread until about 3000 B.C.
文章这里得意思是,虽然E人经常误打误撞的放入酵母,但还是直到3000BC才发明了发酵的面包,答案给出了原因,因为之前用的那种面粉是经过烘烤的,失去了发酵需要的一种成分,再怎么加酵母都发酵不了,排除没有酵母的关系。所以,后来的面粉与发酵面包之间才能causally related
3000 B.C之前埃及人虽然经常无意识的放酵母(yeasts must frequently have been mixed into bread doughs )。但是由于某种原因酵母没发挥作用,所以埃及人不知道酵母可以发酵,一直做着未发酵的面包 (Egyptians made only unleavened bread)。但是3000 B.C时埃及人用了新的小麦,壳不再像以前那样要经过烘烤就可以去掉。还有酵母也是在这一段时间内被埃及人发现了。