[单选题]烯烃不可能发生反应是()反应。
A.氧化
B.酯化
C.聚合

[多选题]在露天使用起重机，应注意（　　）。
A.机身上不得随意安设增加受风面积的设施
B.起重机驾驶室内，冬天可装有电气取暖设备，在作业人员离开时，应切断电源
C.起重机驾驶室内可使用电炉取暖
D.起重机驾驶室内不准用煤火炉取暖

[多选题]关于消防设施说法正确的是（）。
A.灭火器、砂箱等消防器材放在明显、易取处
B.氧气瓶放在施工作业区易取处
C.乙炔瓶放在专用仓库
D.消防器材应使用标准的架、箱

[单选题]该患儿最合适的治疗方法是
A.大剂量维生素D
B.大剂量钙剂
C.先用维生素D后用钙剂
D.先用钙剂后用维生素D
E.在使用维生素D的同时适当补充钙剂

[简答题]Over the last 20 years, energy systems and services have expanded. California now meets its energy needs using a variety of sources from traditional fossil fuels and nuclear technologies to renewable energy resources, such as wind, solar, geothermal and biomass. Technological advances and government standards and programs have resulted in increased energy efficiency, more product and service options and a cleaner environment. Deregulation has promoted competition in energy commodities such as oil, natural gas and, now, electricity.
In the near term, the most dramatic changes in the energy sector are taking place in the electricity industry. As a result of Assembly Bill 1890 (Chapter 854, Statutes of 1996), many Californians will have the opportunity to choose their electricity provider as of April 1, 1998. By January 1, 1999, they will also be able to shop for other electric services, such as metering options. 46)Because of these changes, this California Energy Plan emphasizes