燃气管道（）应设置在管道的上方，并能正确、明显地指示管道的走向和地下设施。
A、警示带
B、跟踪线
C、电子标示器
D、路面标志
参考答案：D
MAC的生物学活性包括()
A．细胞毒作用
B．调理作用
C．免疫粘附作用
D．溶菌作用
E．杀菌作用
根据句意及首字母提示，补全单词。
1. I like English very much. I often go to the English c_____.
2. —Where does the old man l_____?
—He lives in Hainan.
3. I don't like the picture at a_____. I like that one.
4. She seldom speaks Chinese, so her Chinese is p_____.
5. Kangkang and Tongtong are in the same class. They are c_____.
