细菌性痢疾病理改变的主要部位是（）

A.盲肠及结肠

B.回肠末端

C.直肠和乙状结肠

D.小肠

E.空肠、回肠和结肠

. From this simple concept ________ that has caused a great change in farming.

A．has developed a technique

B．has a technique developed

C．a technique has developed

D．developed as a technique has