下列属于电力系统基本要求的是（）。
A.安全
B.优质
C.经济
D.以上都正确
参考答案：D
Brenda is a contemporary artist, but it's obvious that her painting by Picasso. [ ]
A. has reflected
B. has been influenced
C. has been effected
D. has affected
《钢质无缝气瓶定期检验与评定》（GB/T13004-2016）9.2规定，重量与容积测定用的衡器应保持准确，其最大称量值应为常用称量值的（）。
A.0.5倍
B.1.5倍
C.2.5倍
D.3.5倍
