____ can be seen in the chart right here, the air pollution level in the city has been increasing over the last months.

A．What

B．It

C．that

D．As

有关EHEC致病机制正确的是

A．原粒介导LT，ST肠毒素，使肠黏膜细胞胞浆内CAMP增加，液体电解质分泌亢进

B．病原菌黏附于肠黏膜表面并增殖破坏上皮细胞

C．直接侵袭结肠黏膜上皮细胞，释放内毒素破坏细胞形成炎症和溃疡

D．溶源性噬菌体介导SLT_I或Ⅱ型毒素，终中止肠黏膜上皮细胞蛋白合成

E．产生肠集聚耐热毒素致肠黏膜上皮细胞分泌亢进