区域分析法是编制国民经济长期计划常用的方法。

简述首长制的优缺点。

补全对话: 根据对话内容，从方框中选出能填入横线处的最佳选项(其中有两项是多余的)。

A: Hi Betty! 小题1:

B: Yes, I went there with my parents.

A: 小题2:

B: Wonderful. Many famous singers sang at the concert. 小题3:

A: What does it mean?

B: The concert was held for collecting money for the children who are too poor to go to school. 小题4:

A: That’s true.

B: I think people should give them help as much as possible.

A:小题5:

小兵感冒了，咽部发炎没有及时治疗，却引起了中耳炎，这是因为病菌通过（   ）侵染到中耳。

A．外耳道

B．咽鼓管

C．喉

D．耳廓

设计夹具，定位元件的公差，可粗略地选择为工件公差的______左右。

A．1/5

B．1/3

C．1/2

遇到哪些情况不能用水灭火？