---Now the air in our hometown is even       than it was before.

---So we must do something to stop it.

A．better

B．dirty

C．more better

D．worse

急性细菌性痢疾的典型肠道病变为

A．化脓性炎

B．卡他性炎

C．伪膜性炎

D．出血性炎

E．蜂窝织炎