公开招标最显著的特征是招标人以（）方式邀请不特定法人或其他组织投标。
A．招标公告
B．投标邀请书
C．资格预审公告
D．招标文件
参考答案：A
16．－Governments at all levels have to take measures to improve the quality of basic education.
－Exactly. _________, students' homework must be greatly reduced.
A．That's to say
B．What's more
C．Believe it or not
D．In a word
减压塔和真空塔属于外压容器。
