你负责保证你的供货商正确履行合同。为了对合同进行有效的管理，你应该（） A.举行投标

利群大街上原有路灯201盏，相邻两盏路灯相距50米；现在换新路灯又增加了50盏，相邻两盏路灯的距离是多少米？

核酸对紫外线的吸收主要由哪一结构产生？（）

A.氢键

B.糖苷键

C.磷酸二酯键

D.嘌呤环和嘧啶环上的共轭双键

Marko Tskitishvili, an economist, has been studying the drop in the price of the average household computer in the U.S. and wonders if computers should still be considered a luxury good or if it has now become a normal good. He conducts a survey of 500 people and finds the following:

Assume that 1998 is the base date. Based on the above data, Tskitishvili would conclude that a computer is a:（）

A. luxury good with income elasticity of 1.01.

B. normal good with income elasticity of 0.84.

C. luxury good with income elasticity of 1.18.

急性颅内压增高患儿在静脉使用甘露醇时，错误的操作方法是（）。

A.甘露醇如有结晶需加热融解

B.静脉点滴甘露醇前最好要过滤

C.可以与其他药物混合静脉点滴

D.静脉点滴应该在30分钟内完成

E.静脉推注速度不宜过快，以防渗漏