重要的传染源包括()
A.患者
B.隐性感染者
C.潜伏性感染者
D.病原携带者
E.动物储存宿主
参考答案:A, B, D, E
用所给单词的适当形式填空。
1. The teacher asks John _____ (come) to her office.
2. He often _____ (wash) his clothes on Sundays.
3. There _____ (be) a bookstore and two banks in my neighbourhood.
4. In China, everyone _____ (like) dumplings.
5. The coffee shop makes a lot of _____ (drink).
精馏塔釜温度高,下面()操作可以达到降温的目的。
A、减小回流量
B、增大加热蒸汽量
C、增大入料量
D、减小入料量