对流层大气的能量从根本上说来源于（） ["太阳辐射","地面辐射","大气辐射","大气逆辐射"]
When visibility is reduced to about 5 miles, we say that visibility is（）. ["very good","good","poor","moderate"]
以下哪种属于原发性高血压（） ["血管性高血压","肾实质性高血压","内分泌性高血压","没有明确特定原因（综合原因）的高血压"]
动车组列车发售的学生票为全价票的（） ["50%","60%","75%","80%"]
全面效率维修的五大支柱不包括（） ["计划维修","自助维修","设备早期管理","制定标准"]
读者工作应该遵循哪些原则？
