对于稳态噪声，一般以( )为评价量。A．等效A声级 B．A声级 C．声功率级 D．A

补全对话。（共4小题，每小题1分；计4分）

Li Yang: Good morning. Mathew.

Mathew: Good morning, Li Yang.    小题1:  

Li Yang: There's still smog (雾霾) today. We'll have to go to school with face masks(口罩).

Mathew:    小题2: According to the news, PM2.5 pollution is the main problem with air pollution.

Li Yang: Yes, and air pollution has done harm to people's health.

Mathew: So the Chinese government and Chinese people must take action to fight it.

Li Yang:    小题3:   

Mathew: Yeah. Since PM2.5 is mainly caused by vehicles(机动车)and factories, cars with large

emissions(排放)should not be allowed and factories should be closely watched.

Li Yang: I agree.  小题4:   And we suggest making the blue skies return for good.

Mathew: I hope so, too.

N_A为阿佛加德罗常数，下列叙述正确的是（　　）

A．标准状况下，22.4LH₂O含有的分子数为N_A

B．1L1mo1•L^-1NaCl溶液中所含有的Na⁺离子数目为N_A

C．标准状况下，22.4L氯气中所含原子数为N_A

D．一定条件下，56克铁粉与足量的Cl₂完全反应，转移电子数为2N_A

下列税种容易发生税负转嫁的税种是( )。

A．个人所得税

B．印花税

C．企业所得税

D．营业税

用多种工具交替操作使发式成型，称为（XZ）。

A.交替修剪

B.综合修剪

C.多具修剪

D.灵活修剪

导游工作集体的协作原则是( )。

A．相互尊重

B．互通有无

C．求同存异

D．以旅游协议为依据

E．维护各自的利益