a的两倍与b的和,用代数式表示:( ).
2a+b
Where have you been all these days? We are very _____ about your safety. [ ]
A. interested
B. frightened
C. surprised
D. concerned
检测结果通常应以检测报告或校准证书的形式出具,并且应包括客户要求的、说明检测或校准结果所必需的和所用方法要求的()。
A.全部信息
B.全部资料
C.完整数据
D.完整报告