照明控制中每个房间灯开关数不宜少于（）个。 A.1 B.2 C.3 D.4

Which of the following is least accurate regarding obstacles to the efficient allocation of resources in a competitive market（）

A. Taxes and trade restrictions impede the efficient allocation of resources.

B. Quotas result in production of less than the efficient quantity of the good.

C. Public goods, such as national defense, tend to be overproduced because they can be consumed by everyone whether they pay for the goods or not.

如患者患有急性肝萎缩、磷中毒或白血病等疾病时，尿液中可能出现下列哪种结晶（）。

A.尿酸结晶

B.草酸盐结晶

C.亮氨酸或酪氨酸结晶

D.胱氨酸结晶

E.磷酸盐结晶

框架大跨结构中，横梁与柱连接的框架节点（）应做成平整曲线以避免（）

简述多级压缩、级间冷却的优点，如何确定最佳中间压力？

增值税具有以下哪些优点( )。

A．有利于贯彻公平税负原则

B．有利于生产经营结构的合理化

C．有利于扩大国际贸易往来

D．实行差别幅度税额

E．有利于国家普遍、及时、稳定地取得财政收入