在建设工程合同的订立过程中，( )行为是承诺。
A．投标递交投标书
B．双方签订合同
C．招标人发出中标通知书
D．招标人的招标公告
参考答案：C
调整流动相pH，抑制被测组分解离（）
A．正相色谱
B．反相色谱
C．反相离子对色谱
D．离子抑制色谱
E．离子交换色谱
--- What a beautiful city our hometown is! There are many trees ______ of the road!
--- Yes, and ____________ of the trees is growing larger and larger.
A．on both side; a number
B．on each sides; a number
C．on both sides; the number
D．on every side; the number
