凝结水溶解氧规定标准为(),蒸汽含钠量规定标准为()。
参考答案:≤50ppb;≤15ppb5
The first decade of the 21st century ______ breathtaking, non-stop development in China ? [ ]
A. witnesses
B. witnessed
C. will witness
D. had witnessed
在Word2000中,可以对()加边框
A.表格
B.段落
C.图片
D.选定文本